THAMES BARRIER

HC Deb 19 March 1970 vol 798 cc629-51

4.17 p.m.

Mr. Christopher Mayhew (Woolwich, East)

I am grateful for the opportunity of raising the question of the possibility of a catastrophic flooding of the Thames which is raised by the recently published Project Study Group Report of the Greater London Council. I wish also to raise the apparent intention of the Government to recommend the siting of a harrier in Woolwich Reach in the Thames, which is in my constituency.

The danger of such a catastrophe is, unfortunately, very real. We seem to be facing a combination of adverse natural phenomena over which we cannot have control. First the sea off the Thames Estuary is rising by one foot per century. Parallel with this, it appears from the report that central London is sinking, as indeed is the south-east of England, by an amount which no layman can possibly judge from reading this highly technical report, but which seems to be of the order of another one foot per century. The flow of fresh water downstream is increasing and, perhaps most important, there is increased danger of what is known as a storm surge, which is described as "modification of the astronomical tide by meteorological forces". Involved in this, it appears, is a long-term trend in wind patterns. It appears that we will have more north winds in the decades ahead. Altogether, it is a most chilling prospect. There seems to be nothing that we can do to prevent these natural phenomena. Not even hon. Members opposite will claim that if a Tory Government are elected they will prevent the North Sea from rising. They do not seem very interested, either, judging from the numbers of them who are present, to hear this important debate, which affects all London M.P.s. Every M.P. down-river is affected by this subject, and it is very striking to see that the benches opposite contain not a single representative of the Opposition.

Mr. Anthony Royle (Richmond, Surrey)

I do not know whether the hon. Member is implying that there are no representatives of London seats here. I represent a riparian constituency, namely, Richmond, which is greatly affected by flooding. As a result, we are extremely relieved about the barrier which is being erected at Woolwich, so I would ask the right hon. Gentleman to do his homework and just check on what constituencies hon. Members represent before he makes these sweeping statements.

Mr. Mayhew

I was, of course, referring to the emptiness, in particular, of the Opposition Front Bench. Judging from his intervention if I may say so in good humour, that is somewhere that the hon. Member is never likely to find himself—

Mr. Royle rose—

Mr. Speaker

Order. It is in order to raise quite a number of subjects on the Consolidation Fund and the right hon. Member for Woolwich, East (Mr. Mayhew) has chosen one: I think it is about the Thames barrier.

Mr. Royle

The right hon. Gentleman made an allegation. I am in fact on the Front Bench and I am returning there now. I only intervened to point out—from the back benches—that I am a riparian Member.

Mr. Mayhew

I am sorry. I confused the hon. Gentleman's political status with his geographical position.

In the area threatened by flooding of this kind, 1,200,000 Londoners live and during the day, after the daily influx, there are 1,500,000. This catastrophe, as the report makes clear, would flood 48 miles of underground track and 70 underground stations. It would severely damage many famous buildings. The Tate Gallery houses many great works of art in its cellars which would be flooded. Palace Yard, no doubt, would provide admirable moorings for hon. Member's boats if this happened.

Action is urgently needed. The report lists 50 different designs for various barriers in different sites on the Thames. The House will not want me to go through all 50, discussing their merits, but, in practice, the report concludes by offering us a choice between two alternatives—first, a drop-gate barrier at Woolwich, combined with raising the banks down-stream by a substantial amount, about 6 ft., or, alternatively, a drum-gate barrier at Crayfordness, at Long Reach, with limited bank raising upstream of one to two ft. Without going into all the technical details, those are the two proposals in effect suggested by this plan.

What are the criteria by which we should decide between these two projects? Here is where the report and the Government begin to go wrong. They are right, of course, to say that the overall primary objective is the safety of Londoners. No one can possibly disagree with that, but they go on to say that the second criteria is the cost, and the third is the inconvenience to shipping. In all this report and in the Government's statements, the question of amenity is nowhere mentioned. Of course, the proper criteria on which to judge between these two projects are, first and foremost, safety, second, amenity, third, cost, and fourth, shipping. I want briefly to judge these two proposals by those four criteria.

First of all, on the safety of Londoners, the verdict must go, on the basis of the report, to siting the barrier at Crayfordness. I would draw the Minister's attention particularly to page 58 and to the paragraph in the section "A barrier at Crayfordness" which reads: To reduce the number of closures each year to that acceptable it would be necessary to raise banks upstream by one to two feet above their present level. This should be done as a matter of extreme urgency as it would improve the present defences in the shortest time. That last sentence is of particular importance. It means that, during the six years which would be necessary if the Woolwich site was chosen, there would be no increased defences against the possibility of catastrophic flooding. If the Crayfordness site were chosen, an immediate start could be made, as the report recognises, on remedial action of great importance—namely, bank raising—which would have to be done in any case, and which could be started straight away. Thus, on the criterion of safety, the verdict should go against Woolwich and for Crayfordness.

The second criterion is amenity. I have said that there is no reference in the report to it. This is incredible. One would have thought that, nowadays, even technocrats have heard of the interest of Parliament in questions of natural environment, destroying the countryside, bad town planning and pollution—all the environmental questions which everyone is talking about today. Not so the compilers of this G.L.C. report, judging from their statements, not so the leaders of the G.L.C. or the Ministers concerned in taking this decision.

What is involved in amenity? First, the structure itself. There will be four enormous, colossal, concrete piles, each one almost as high as St. Paul's Cathedral. Where will it be put? Reading the report makes one think that these people must have gone backwards and forwards along the Thames until they found a site which would cause the maximum inconvenience and loss of amenity to the local inhabitants. It is true that they did not actually choose to put this monstrous erection opposite the Royal Naval College at Greenwich—I cannot think how they missed that—but they have taken the second worst site, from the point of view of loss of amenity. That is the last remaining site on the Thames for development—the site of the old Royal Dockyard in my constituency, a site which is the jewel in the eye of the local council, a site where they are proposing to develop so as to preserve the historical features of the site, where they are planning a promenade along 220 yards of the river front, where they are planning to build an attractive group of homes for 650 families, a site for which they have paid £500,000 to the Government for developing it and on which they are now paying £50,000 a year in interest, at the same time. Now what are they supposed to do? A weaker-minded council might say, "Since the Government cannot decide, and may make the monstrous decision to site the barrier here, we will not go ahead with our development". Although I am not politically of its persuasion, I am glad to say that the borough council has decided to defy the Government to take this disgraceful decision.

I might be wrong on this point. I have not yet inspected the amenities at Crayfordness, and it may be that the Minister will tell me that it is a great beauty spot and that there is a bird sanctuary or ancient cathedral on the banks. But let the Minister justify Woolwich, as against Crayfordness, on this amenity ground.

Let us suppose that the barrier has to be at Woolwich, which I am sure is a wrong decision. Why does one have to have it opposite the dockyard site, as all the plans and proposals show? Why not have it a little further up river at the old site at Woolwich of the Associated Electrical Industries factories? There is a strong suspicion in the minds of my constituents that the reason why the dockyard site is chosen and not the A.E.I. site is that, when the survey was taken, the dockyard site was simply a derelict dockyard and the A.E.I. site was one of busy factories. Today, the dockyard site is the scene of an exciting projected new development, and the A.E.I. factories have been closed. If the barrier has to be in Woolwich, why has the dockyard site been chosen instead of the A.E.I. site?

There are other considerations on the amenity question besides that of appearance and the domination of this site by this vast structure. There is the cost and the inconvenience to all the occupiers of the river front downstream—the frontagers as they are called. In Greenwich alone, industry and commerce occupy 24,250 ft. of river bank. The position is the same all the way down the river. Consider what this means to the business men who are involved in this. The report says: Increases in the flood protection level of the order of 6 ft"— and 6 feet is involved in the choice of Woolwich— cannot be achieved by merely adding material to the top of existing walls and banks as structural failure will result. The realignment and rebuilding necessary to achieve the substantial increase in level needed is likely to disrupt the river front activities. The most obvious disruption would be to wharves serving shipping and lighterage. In addition to the loss of the facility[...] while structural work was carried out, there would be further disruption while facilities such as wharf cranes were modified to serve in the changed conditions. This is what is involved in placing a barrier at Woolwich instead of at Crayfordness.

Mr. A. Royle

The implication of much of what the hon. Gentleman has said is that the Greater London Council is taking no interest in the amenities of London as a result of the positioning of the barrier. I should not like to argue in favour of Crayfordness as against Woolwich, about which I am sure that the hon. Gentleman knows more than 1. But he ought to underline the fact that the present Greater London Council, whatever its political views, have taken a great interest in the amenities of the whole capital city. The idea of putting up this barrier at all is to improve the conditions for the whole of the capital city, including my constituency, that of my hon. Friend the Member for Chelsea (Mr. Worsley) and conditions right across the city. Inevitably, some areas in the immediate vicinity of the site of the barrier will have the unattractive view of something which will improve the amenities for all the area.

Mr. H. J. Delargy (Thurrock)

Although I am in complete agreement with what my hon. Friend the Member for Woolwich, East (Mr. Mayhew) has said, he is speaking as though the site has already been definitely chosen and as though a decision has been made. Surely this is not so?

Mr. Mayhew

I wish very much that I could agree with my hon. Friend the Member for Thurrock (Mr. Delargy). My hon. Friend the Member for Erith and Crayford (Mr. Wellbeloved) has been working closely with me. I am sure that he will agree with me that, talking to Ministers and experts on this, we have gained the very strong impression that minds have been made up almost even before the writing of the report. As to the amenities, I hesitate to go into the Greater London Council's dedication to amenities—especially in view of the forthcoming G.L.C. elections—which divide the hon. Member for Richmond, Surrey (Mr. A. Royle) and myself and might lead to continuous and long-drawn-out altercation. But I want to see the barrier at Crayfordness rather than Woolwich on amenity grounds.

I have just made the point that many thousands of business men and commercial interests downriver will be faced with a considerable problem if Woolwich is chosen. Any idea that they will pay £150 a foot for raising their banks by 6 ft. is something about which the Government can think again. Will the Minister assure the House that there will be no question of the cost of raising these banks falling on the individual businessmen and others who occupy footage on the river bank?

Having dealt with the safety and amenity points, the third factor is the cost. Here, I need not go into detail. The report shows that Woolwich is cheaper than Crayfordness by the time that one has added together the costs of the structure itself, of the bank raising, of paying compensation and of the delay to shipping. The cost for Woolwich is estimated at £45 million and Crayfordness at £48 million. It is possible that those figures may be challenged by my hon. Friend the Member for Erith and Crayford, because I know that he has made a careful study of them. But on the report's own showing the cost to Crayfordness—

Mr. James Wellbeloved (Erith and Crayford)

My hon. Friend will be aware that, when he and I had the honour of meeting the Minister on this matter, our right hon. Friend made it quite clear that no proper investigation of the Crayfordness site had taken place and that therefore it was not possible to put a calculated price on the cost of Crayfordness. This was one of the points on which we both condemned this proposal.

Mr. Mayhew

I am grateful to my hon. Friend for reminding me of that. There is also the uncertainty of the siltage factor. The survey of the siltation factors, which are tremendously important, had not been made when this report was published. There is a great question mark on the Woolwich site as regards the siltation factor which still has to be resolved when further tests have been made.

The fourth point is the inconvenience to shipping. It is a highly technical argument, and I shall not weary House with it. The P.L.A., whose interests are at stake, on balance prefers the Crayfordness site to the Woolwich site, though I agree that it is a marginal preference. It is perfectly clear that the tenor of the Government's talk in favour of a site at Woolwich Reach is mistaken. They have under-estimated the urgency of the need for immediate bank raising and not waiting for any barrier. They have also given no consideration to the amenity arguments which all tell against siting the barrier at the Royal Dockyard, Woolwich.

Finally, I am glad to see that legislation will be needed before the Government can proceed, but I must warn the Minister against expecting that his legislation will have an easy passage if he continues to ignore the important factors to which I have drawn attention.

4.39 p.m.

Mr. Marcus Worsley (Chelsea)

I must apologise to the hon. Member for Woolwich, East (Mr. Mayhew) for not being present when he began his speech. Unfortunately, I was addressing a constituency meeting and that is why I arrived at the House a little late. I thought it a pity, as I came in, that the hon. Member appeared to be making something of a party issue of the barrier. The fact of the matter, as I hope the hon. Gentleman knows, is that this is not a party issue. I think that he appreciates that.

Mr. Delargy

How can it be a party issue if my hon. Friend is attacking his own Government?

Mr. Worsley

The hon. Gentleman may have missed some of the nuance at the beginning of his hon. Friend's speech. The hon. Member for Woolwich, East knows that a group of hon. Members on both sides of the House have been studying the problem under the chairmanship of the late Mr. Gresham Cooke, the former Member for Twickenham. The issue is not simply a matter for those hon. Members representing downstream constituencies. It is also a matter for hon. Members representing constituencies further up river.

I do not wish to follow the hon. Gentleman into the somewhat internecine discussion which is taking place on the other side of the House about the siting of the barrier. I am concerned with the interests of my constituents, and for two reasons. The first is the danger of flooding. I have always been in two minds about how much one should say on this issue. I cannot imagine any single issue which could cause more alarm if the public mind became seized of it in a way which caused something like panic. On the other hand, I am conscious of my responsibility as an hon. Member representing a constituency almost all of which is at risk from flooding. In my opinion, the report to which the hon. Gentleman referred shows practically the whole of my constituency as being at risk.

This is a matter on which a decision must be taken and on which action must follow rapidly. Under successive Governments, a great deal of time has been occupied in consultation, planning and studies. That must be brought to an end as soon as possible. A decision is needed to allay the doubts and fears of the people of London. In view of that, I seek from the Government as precise as possible a time table of what they hope to see happen. Both as a London priority and as a national priority, I hope that this will be high on the Government's programme from now on.

So much for the safety angle. There is also the amenity angle. In recent years the Greater London Council has taken a great interest in the amenities of the river, as the hon. Gentleman knows, though he paid rather churlish credit to it. It has had a working group discussing the matter. Some months ago, when I took up the case of the very famous houseboats on Chelsea Reach which are threatened because of proposed road changes, I found a great response from the members and officers of the Greater London Council, who have a notable awareness of the amenities of the river and what should be done.

As I say, I am neutral in the disagreement which is occurring on the Labour benches. If one of these two schemes is put forward, it can do more to improve the amenities of the upper stretches of the river than any other single factor. The lowest level of the river could be controlled, and we could get away from the greatest detriment to amenity, which hon. Members can often observe by going on to the Terrace in summer, namely, the presence of the mud flats.

I am anxious to see one of the two schemes go forward, because I want to see the fear of flooding removed. Hon. Members must not forget that, over the decades, the risk of flooding increases steadily. There is a time scale of increase in risk, though I admit that it is slow. For that reason and for the sake of amenity, I want to see rapid action on this matter, and I hope that the Minister will be able to give very much firmer commitments on behalf of the Government.

4.45 p.m.

Mr. James Wellbeloved (Erith and Crayford)

I begin by congratulating my hon. Friend the Member for Woolwich, East (Mr. Mayhew) on having the initiative to put down this subject for debate and on having the good fortune to be drawn at the head of the list. The issue of a Thames flood barrier is a matter above party politics and one that affects the whole London area which lies on the tidal flood plain.

My hon. Friend referred to the factors which contribute to the flood risk in London: the North Sea surge, the high tides, the downward flow from Teddington weir and the drop in the level of the land, thus increasing the mean tide level. It is a serious risk. There are 65 square miles of the London Metropolis on the flood plain. That is the area under the control of the Greater London Council, and it is all subject to a flood risk. In the 65 square miles about 1¼ million people live in some 350,000 houses. The risk to human beings, families and the property of ordinary people is very serious.

Looking at the situation of London as a whole, we have to bear in mind the considerable number of power stations and telephone exchanges on the London flood plain. Mr. Deputy Speaker, I would not like to incur your displeasure by widening the debate—

Mr. Deputy Speaker (Mr. Harry Gourlay)

As a matter of fact, the hon. Gentleman is giving me some difficulty already. I do not know to which Estimate his remarks are related. We are discussing Clause I, Vote 6 L.4, which is concerned with surveys. Perhaps he will relate his remarks to it.

Mr. Wellbeloved

They are related to it, because we hope to encourage the Government to make available the necessary finance to provide a London flood barrier under the appropriate Vote.

I was about to say in passing that the part of London on the flood plain is also subject to a serious flood threat to three of the major sewage works which serve the sanitation requirements for a large part of the area.

The areas about which my hon. Friend and I are concerned, Thamesmead and the lower reaches of the Thames which come within the area of the Greater London Council, have been subjected to repetitive flooding over a considerable number of years. I join with the hon. Member for Chelsea (Mr. Worsley) in expressing condemnation of all Governments who have held power since 1953—the last occasion of which the Thames flooded—for their lack of positive action to protect London from this danger.

In 1953, a commission was set up. It reported, and two consultants were appointed to carry out a feasibility study. Both of them produced plans for a barrier to protect London at Long Reach, Purfleet. However, I understand that they also destroyed each other's recommendations.

We then come to the period of office of the present Government. They appointed Professor Bondi, an eminent mathematician, to carry out a further survey of the problem. The present Minister has failed to put into operation the recommendations which Professor Bondi made in regard to London's Underground. My hon. Friend reminded us that there are 46 miles of Underground track and 70 Underground stations which today are at risk from flood. In his report, Professor Bondi recommended that there should be a trial evacuation carried out on London's Underground. As far as I have been able to ascertain, that recommendation has never been put into operation. In my judgment, it should have been, because a disaster of immense magnitude would hit us if the London Underground system were flooded. Professor Bondi foresaw this and took the very wise precaution of recommending a trial evacuation so that we might be certain that the emergency arrangements would work. Professor Bondi has clearly said that delay invites disaster and the longer the delay the greater the disaster that could befall London.

The current proposals in the report now before the Government provide for a barrier at Woolwich or Crayfordness. This is matter of immense significance to those who represent riverside constituences. My hon. Friend referred to the amenities at Woolwich and I sympathise with his point of view. I assure him of my full support against the siting of the barrier, with its massive towers, at the Woolwich end. It would be an outrage to desecrate the amenity values of Woolwich in that way.

My hon. Friend also referred to the amenities at Crayfordness. If the proposal for a barrier at Crayfordness should become a reality, the report makes it clear that the type of barrier would not be a tower drop gate barrier but what is delicately known as a drum gate barrier, a barrier that pops up from the river bed. Therefore, my constituents and the constituents of my right hon. Friend the Member for Dartford (Mr. Sydney Irving) would not be affected, other than by the inconvenience caused by the construction which would take place over the years. If the barrier was sited at Crayfordness there would be no long-term loss of amenity as would be the case if a massive tower structure were erected at Woolwich.

If the barrier were put up at Woolwich, what would it mean to people who operate businesses and carry out their lawful occupations on the banks below Woolwich? At the moment the river banks in my constituency at Erith and Crayford are somewhere between 17 ft. O.D. Newlyn and 20 ft. O.D.N. The proposals in the report are that if the barrier goes at Woolwich, it will be necessary to put 6 ft. on top of the existing river bank wall right through my constituency. I have already had consultations with a number of industrialists and other riverside users and have met the chambers of commerce. Considerable apprehension is being expressed by the riparian owners because they claim that a further 6 ft. on the bank to bring it up to 24 ft. O.D.N. would in some cases completely destroy the viability of their industrial undertakings.

It is not only a question of bringing the bank up to 24 ft. O.D.N. Because of the nature of the subsoil, which is 30 ft. of peat and silt that has been built up over the years, it will be necessary to pile-drive the river bank walls, or to have a ledge some 60 ft. wide to support the weight of the increased height of the wall from further slippage or sinkage. It is not only a matter of a 6 ft. wall. There is the possibility that the wall would have to be on a ledge 60 ft. in width along the length of the bank below the Woolwich site, if that is the site chosen for the barrier.

The present position is that further reports are being called for on siltation. It is already being suggested that if the barrier were at Woolwich by the entrance to the King George V dock the siltation problems might make that dock difficult to use. It would need a considerable amount of dredging. Therefore, a special report is being prepared.

I also understand from meetings with the Ministry a short while ago that further reports on the cost of the Crayfordness site were also being prepared. Could the Parliamentary Secretary in his reply say a little about the dates of these other reports which have been promised, because it is essential that we should have adequate time to study and discuss these extra reports before any final decision is made. My own local council, the London Borough of Bexley, has already come down strongly and firmly in favour of the barrier being sited at Crayfordness. I understand from my hon. Friend the Member for Woolwich, East that the London Borough of Greenwich has done likewise.

The Port of London Authority has said that marginally it favours the Crayfordness site. I hope my hon. Friend the Parliamentary Secretary will add to that list the voices of his two hon. Friends the Member for Woolwich, East and myself as also favouring the Crayfordness site. This combination of support must have some effect on a consideration of this matter. In our judgment it is vital that the barrier should go downstream, thus affording the maximum protection to the maximum number of Londoners.

Finally, I wish to refer to the new town development at Thamesmead. I appeared at the public inquiry of the Thamesmead proposals held in October, 1967. The Greater London Council gave firm and positive evidence to the inspector that it would prefer a Thames flood barrier to be sited downstream of that development. The Ministry's inspector in this report on the inquiry also firmly came down in favour of maximum flood protection provided by a barrier situated downstream from Thamesmead. This is a vitally important matter which must be weighed when a decision is being reached. Here is a site embracing some 60,000 people in an area that is known to be on the tidal flood plain. It is not going there by accident, but because of a deliberate act of planning. Those who have conceived the plan and authorised it have an absolute responsibility to see that those residents are given maximum protection.

I ask my hon. Friend to bear firmly in mind the point that the inspector and the G.L.C. at the inquiry said that maximum protection could be given by a barrier downstream. I congratulate my hon. Friend on having given me the opportunity to join with him in his representations. We await with great anxiety the decision that will be made about the siting of this barrier.

4.59 p.m.

Mr. H. J. Delargy (Thurrock)

I apologise to my hon. Friend the Member for Woolwich, East (Mr. Mayhew) for not being in the House to hear his opening remarks. I intervene in the debate for two reasons. The first is to draw attention to the very large number of people in the riverside authorities who will be affected by this barrier. We have almost 20 miles of the banks of the River Thames within our constituencies and the people who live there are obviously extremely interested in what is going on in their neighbourhood.

The second reason is that if the proposal is accepted for the barrier to go at Crayfordness it will end up in Purfleet, which is in the district of Thurrock. Therefore, we are closely interested in the matter. I agree that no decision can be taken tonight. Legislation will be required, and then we shall be able to speak at greater length.

I have the utmost sympathy with what my hon. Friends have said. I support them in reminding the Government that if they think that this first proposal can be pushed down our throats, the Bill will not have as easy a passage as they might be led to expect. However, I will not speak about these matters now.

I have one great grievance—namely, the lack of consultation throughout with the local authorities and with riverside Members. There have been two meetings with the Minister, particularly with the noble Lord, Lord Kennet, who at all times is extremely well informed and courteous. The first meeting was adjourned so that Members could study the report. When the second meeting was called we still had not seen the report. I am waiting for a third meeting to be called, but I have not yet seen the report. It is very bad, on such an important matter, that hon. Members who represent riverside constituencies have not been kept better informed.

That is all that I want to say at this juncture. I congratulate my hon. Friend the Member for Woolwich, East on having introduced this subject, I am grateful to the House for listening to me, and I apologise for having missed the first few minutes of the debate.

5.2 p.m.

The Joint Parliamentary Secretary to tine Ministry of Housing and Local Government (Mr. Reginald Freeson)

I also join in congratulating my hon. Friend the Member for Woolwich, East (Mr. Mayhew) on introducing this subject, because it gives me an opportunity briefly to review the historical position and to describe the position that we have now reached before the major decisions, to which hon. Members have referred, are taken.

As much stress has been placed on the history of the matter and the time it has taken to reach the present position, perhaps I might briefly review the history.

Flooding of the low-lying areas of London has occurred on a number of occasions in the past and the danger that this has reflected has been met by the building and raising of flood defence banks along the shores of the estuary. The last such raising took place in 1930 after the severe floods of 1928.

Nothing like that was repeated until the exceptionally high water of 31st January to 1st February, 1953. On that occasion considerable flooding occurred of low-lying areas to the east of London, and the Departmental Committee on Coastal Flooding, which became known as the Waverley Committee, was appointed to investigate and to report on measures to combat the danger. One of the recommendations was that a barrier structure be investigated for the protection of the London area.

A report on a proposed flood barrier in the centre of Long Reach was produced in 1958 and submitted to the then Minister of Housing and Local Government. This was not implemented, as the navigational difficulties during the construction period were considered unacceptable. Thus, a further report was submitted in 1965, following a change in Administration, putting forward two proposals which, however, raised great technical difficulties and were extremely expensive.

In order to obtain an independent assessment of the problem, Professor Bondi, to whom reference has been made, who was at that time Professor of Mathematics at King's College, was asked to report on the subject, which he did in 1967. He considered the flood risk to be quite unacceptable and suggested investigation of barrier sites in Halfway Reach and Woolwich Reach and a barrage site upstream of the entrance to the West India Docks.

I understand that an exercise in evacuation of the London Underground, which he recommended in his report, has been undertaken by London Transport and found to be satisfactory. I have not got the details with me, but I shall be glad to pursue the point in further detail subsequently if my hon. Friends wish.

Mr. Wellbeloved

When my hon. Friend checks the facts he will find that it was an extremely poor trial evacuation. It was purely an operational headquarters exercise. There were a few phone calls, but no trial evacuation of human beings was carried out as had been recommended by Professor Bondi.

Mr. Freeson

I was about to say that I suspect that on further investigation I should find that it was a feasibility study which was undertaken. As the matter has been raised specifically by my hon. Friend, I will pursue it to see whether I can satisfy him further following this debate.

Soon after the report was received in 1967, the Minister invited the Greater London Council, in January 1968, to undertake urgently an investigation into the construction of a movable barrier at three suggested sites and a fixed barrage at a fourth site. The G.L.C. agreed to undertake the investigation in the light of the Government's determination to reach a decision as quickly as possible, and it reported on 20th January this year.

The report shows that the danger of a tidal flood is real and imminent. A tide of 1953 height today would overtop the existing defences in London. A worse surge than that, which could happen, would be a large-scale disaster involving probable loss of life and about £1,000 million worth of damage. Though one must regard calculations of this kind with some reserve, the best estimate of probabilities now is that in the years 1970–79—in other words—virtually over the next decade—the chances of "bank full" conditions—that is, of waters lying level with the top of the Embankment in London—are one in ten in any one year. The chances of the Embankment being overtopped by six inches are one in 20, and by one foot—which, if it were to last for any length of time, say, an hour or more, would cause a major disaster—one in 34 in any one year. These odds, however, are shortening all the time, because the height of the Thames tides in relation to the level of the land is rising by about 2 feet 8 inches a century. These figures make clear that a surge tide is bound to recur sooner or later, whatever the odds, on or against, the calculations may be in terms of accuracy.

The report concludes that a further detailed investigation should continue into the relative advantages of two types of movable barrier. The first is a "rising" barrier at Crayfordness, to which reference has been made, and the second a "drop—gate"—portcullis or guillotine—type of barrier at a suitable site in Woolwich Reach.

The first of these proposals is undesirable for several reasons. It would be very expensive, would take too long to construct, and its closure would involve a great deal more interference with shipping than would a barrier at Woolwich, because the site would be downstream of the Royal Docks. Also, consultants advise—this is very important—that the reliability of a submerged barrier rising from the river bed is open to grave doubt. However, I stress that whatever comments I make on this matter, no final decision has been taken and the Minister has not yet expressed an official view on the direction in which he will move when the various reports are finalised.

The alternative, a "drop gate" barrier, which we understand would be reliable, could not practicably be constructed further downstream than the Woolwich area, because, if it were below the Royal Docks, the shipping using it would require a wider opening than the practicable maximum of 450 feet. In other words, 450 feet would not be wide enough for ocean-going shipping.

On the assumptions that a drop-gate barrier is the right type, as being quickest, cheapest and most reliable, and that it should be sited as far downstream as practicable, the best site would be in Woolwich Reach, just upstream to the entrance of the Royal Docks, with concomitant raising of the banks of the river downstream.

However, the first results of experimental work with a model, by the Hydraulics Research Station—the completion of which is still awaited—suggest that a structure here would produce siltation opposite the entrance to the Royal Docks. It is too early to say whether this objection will prove fatal to the project. Accordingly, a site further upstream in Wolwich Reach is being examined and this looks promising so far. Site borings will be completed during next month and hydraulic investigation during May.

A third possibility is a site in Black-wall Reach, for which hydraulic tests will be complete by the end of this month. A barrier here would have a smaller opening and there are several questions still to be investigated about the strength of the geological foundations and the load that they could practicably bear. A structure here would be cheaper than at Woolwich, but, on the other hand, there would have to be another eight miles of riparian wall-raising over and above that which would be necessary if the downstream Woolwich site were chosen.

All of these various aims, which are directed towards making decisions which will be effective, have followed in quick succession on the receipt of the report for which we had asked urgently and which was effectively carried out by County Hall.

Mr. Mayhew

Would my hon. Friend answer the specific question I asked—why cannot we urgently start on bank raising? He said that it would be 10–1 in respect of bank-full conditions every year for the next 10 years and 20–1 against six inches above the bank. The advantage of the Crayfordness scheme is that it would involve immediate bank raising of one to two feet throughout, and that would be of great benefit from the point of view of the safety of Londoners.

Mr. Freeson

My hon. Friend will recall that he and others put that point in the consultations with my right hon. Friend and the Joint Parliamentary Secretary. I understand that in the course of those discussions it was pointed out that it would be rather expensive and not very adequate to do this sort of operation in a piecemeal fashion—that is, separately from the major project being put in hand.

We asked the G.L.C. earlier this month to investigate this matter further and we are awaiting its report to see whether some work can be put in hand in respect of bank raising, ahead of the major project, whatever decision is reached, to meet the point raised by my hon. Friend which has been widely stressed. It am not in a position to say what the conclusions will be and no doubt we shall receive that report as soon as the G.L.C. has prepared it.

I come to the question of the effect on amenity. A drop-gate barrier at Woolwich would have twin towers 175 ft. high, with a main sluice-gate between them 450 ft. long and 55 ft. deep. There is no doubt that this would be a prominent feature and, as has been indicated today, that some people would not like it.

Mr. Mayhew

Nobody would like it.

Mr. Freeson

It is a little early to suggest that nobody would like it. Some might.

Mr. Delargy

People downstream would not.

Mr. Freeson

It is not possible at this stage to come to a conclusion about general public opinion on the point, at least not for the purposes of this debate. I accept that there would be objections—indeed, there are, as the debate has shown—but it would be wrong to come to a categorical view at this stage that it would be ill-received by everybody. Indeed, I suggest that it might be wrong to come to a categorical view that even those who, understandably, are anxious about it now, would stick to their view of such a scheme as it evolved, wherever it was sited.

If shipping movements decline and further investigations show that there are no prohibitive problems of ground-water, siltation or upsteam water-pollution, it later may prove possible to use the barrier for half-tide control, with resultant benefit to the appearance of the river upstream, because the mud-banks now exposed at low-tide, which are quite unsightly, would be permanently covered. The barrier would be closed at half-ebb as a routine and reopened at half-flood.

This would not only be of advantage to amenity but would mean that closure would not be dependent on a surge warning, so that all risk of error would be eliminated. The idea may turn out to be impracticable—it has yet to have conclusions drawn on it—but, in any case, it is in the nature of an "optional extra" which need not be decided yet and does not affect the immediate questions of type and siting of a barrier.

It is fair to say that adjacent works need not necessarily be unsightly. My hon. Friend the Member for Thurrock (Mr. Delargy)—speaking from the estuarial point of view—may know that this visualises a good deal of grass banking and not what some have referred to as unsightly concrete masses which would add nothing to amenity. At this stage, when the argument on amenity is by no means conclusive, it is possible that people will reach the conclusion that the design of such a project, wherever it is sited, would be a striking attraction and that the works associated with it would be attractive to the amenity of the neighbourhoods concerned.

Reference has been made to costs. A barrier in Woolwich Reach, though larger than any similar structure so far built anywhere in the world, would not represent an unreasonable extension of civil engineering practice, so that the estimates of cost are reasonably reliable.

A drop-gate barrier would cost approximately £30 million. To raise the river walls downstream to the G.L.C. boundary wall would cost about £20 million. In addition, it would be necessary to raise the river walls in Kent and Essex, even though these were raised after the 1953 tide.

A good deal more work is necessary before accurate estimates can be made of the cost of the extra protection for Kent and Essex or of its timing, but the ultimate cost might be about £35 million. This is based on the assumption that there would be a general raising of walls by six feet; that is, three feet to ensure safety under present conditions and three feet to ensure safety for about 100 years following the completion of the project.

In addition to the capital costs, there would be costs imposed on shipping by delays when the barrier was closed. If the pattern of shipping in the river remained as it is at present, the capitalised value of these delays would amount to about £5 million. It would be less if, as seems probable, the use of docks up-steam of the Royal Docks declines.

Mr. Mayhew

On the question of the cost of the banks, are not the figures which my hon. Friend has given greatly in excess of those in the report? Would he say what the cost of the Woolwich scheme, of raising the banks downstream, would he and, therefore, what would be the total cost of the project?

Mr. Freeson

I thought that I had done that by referring to the cost of the works. This is, perhaps, where uncertainty has crept into my hon. Friend's mind. I included the cost of the works beyond the G.L.C. boundary—the report with which we have been dealing so far.

Mr. Mayhew

I see the point.

Mr. Freeson

On the question of timing—stress has been placed on the urgency of the matter—even with the utmost speed, it will, from the time when authority is given by the Government, take about two more years to complete the studies, to design the barrier and to obtain powers for its construction, including the legislative proposals which will be involved. If construction began in 1972, the barrier would not be in effective operation before 1977. It is a major operation, the largest of its kind that has been seen anywhere in the world so far.

I should stress in referring to the timing that this is not said in any way to suggest that the Government are not determined to get ahead with implementing policy in this matter as rapidly as they can. We are determined that we should do so and that London and the lower Thames-side should be defended against tidal floods. Several meetings have taken place with my right hon. Friend the Minister and the Joint Parliamentary Secretary. I take very much the point about the need for further consultation. I am disturbed to hear that there has still been a failure in the supply of copies of the report. I shall certainly take note of that and investigate it when I get back to my Department. I agree that in a matter of this kind there is the utmost need for consultation, not only with riparian hon. Members but with any other persons who have special interests in the future of the City, concerning the river-side.

I have tried in my review to deal with all the points with which I could deal this afternoon. I realise that there is bound to be continuing anxiety about this matter until the final decisions are taken. I am glad to hear that the local authority most immediately concerned has decided to proceed with the major part of the scheme on the river-side which might be affected by the Government's decision.

I understand—this was confirmed when I discussed the matter personally with representatives, elected members and officers of the authority when discussing housing matters a little time ago—that, were the scheme to go ahead at Woolwich, it would affect only a relatively small site. This has led them to make the decision to proceed nevertheless with the development proposals which they have in mind. This is what was put to them by me and others from the Department when we met them a little time ago to discuss housing matters. I am glad to hear what has since transpired.

Mr. Wellbeloved

Before my hon. Friend leaves the point about costs and timing, may I say that what he told me this afternoon increases my fears and anxieties that the decision has already been taken to use the Woolwich site. Can he tell us what further investigations are to be carried out on the Crayfordness site? Can he assure us that this is not a "kid stakes" but that genuine serious investigations are taking place and will be laid in report form before a decision is taken?

Mr. Freeson

Of course I can give that assurance. I am sorry that I did not specifically state it when I was referring to the Blackwall proposal and various alternative choices. Two examinations are going on and are being costed, as far as it is possible to cost these things at this stage, on a feasibility basis. In the course of this, clear conclusions will be reached by the Government through the various Departments concerned and eventually, when all these reports have been completed, a recommendation and proposals will be submitted to the House and will be announced so that all interested persons may be informed. It is not possible for me to say that there will be an individual report for the House about the Crayfordness site, but there will be conclusions on the basis of studies which are being genuinely undertaken on the various alternative suggestions. I hope that that assurance, even if it does not allay anxieties as to what and when the decision will be about Woolwich, will satisfy my hon. Friend to some extent.

I recognise the anxieties. We are pressing ahead as rapidly as we can. The important point in the end is to take account of the needs of London as a whole. On the three main points emerging from the Report which is before the Government from the G.L.C., I hope that it will be accepted that while the report itself may not have referred specifically to amenity, as a major criterion we have that aspect very much in mind.