HC Deb 03 August 1965 vol 717 cc1268-70
Q4. Mr. A. Henderson

asked the Prime Minister what reports he has received from his Scientific Advisory Committee about the need for on-site inspections for the purpose of verifying underground nuclear explosions; and whether he will make a statement.

The Prime Minister

If, as I assume my hon. and learned Friend is referring to the Advisory Panel on Disarmament its deliberations and reports are confidential.

Mr. Henderson

Would not my right hon. Friend agree that the number of underground explosions which cannot be nationally verified is so small as to justify the risk of entering into a comprehensive test ban agreement excluding on-site inspections, more especially if the agreement contains a renunciation clause? Can the Prime Minister say whether such an approach is being taken at the Geneva Conference?

The Prime Minister

While it is true that the techniques for verifying these matters without on-site inspections have improved, it is not the case where I think we can take a risk on this matter, not at this stage. What we have suggested, as indeed both sides said in the House during the recent foreign affairs debate, is that, as both Governments have pressed for for a year or two now, there should be a meeting between Western and Soviet scientists to examine Soviet claims that this can be properly identified from a distance. This is one of the points that we have already started to press at Geneva. I am sorry that I cannot yet publish the speech of my noble Friend at Geneva. As soon as it is declassified, as soon as it is no longer confidential, it may be useful for the House to be able to see it.

Mr. Lubbock

Is the Prime Minister aware that there have been a number of Questions on this subject, both in the previous Parliament and in this one, and that all we have ever been told is that a certain amount of risk exists in small nuclear explosions which might not be detected? Will he consider publishing a White Paper setting out what these risks are, and why an explosion with a yield of less than 5 kilotons would be militarily significant at all?

The Prime Minister

It might easily be because the purpose of the test ban agreement, even though it was limited, was to stop the nuclear arms race. The arms race depends more than anything on one side fearing that the other side will get ahead. As long as it is possible to have tests of this kind, even quite small in terms of total yield, but possibly significant in terms of technological advance, one side will fear that the other is getting ahead and will tend to intensify the arms race. As techniques improve, we look forward to a situation when this can be done without on-site inspection, but our advice is that we have not got there yet.

Mr. Paget

In view of the size and complexity of the whole nuclear set-up of the major Powers, may I ask my right hon. Friend whether he is really suggesting that the balance of power could be shifted by small underground tests?

The Prime Minister

Not the balance of power, I think, because everyone recognises that there is a very real balance of power between the two major nuclear countries. On the other hand, I think that both nuclear countries, and indeed the whole world, want an assurance that the nuclear arms race will come to an end. We have had many other proposals in that field, and we must recognise that the possibility of technical advance, if that is the right word, and technological developments, could set up a big and important competitive reaction; first within these small developments, and then perhaps spreading more widely.

Mr. Hogg

Is it not a fact that the Soviet authorities have so far declined a meeting between Russian and Western scientists, and has the right hon. Gentleman so far been able to ascertain what reasons they have for this failure to accept our proposals?

The Prime Minister

I have not. I think that the position is still as it was when the right hon. and learned Gentleman was last concerned with it. The Soviet authorities have declined this meeting and so far they have not been willing either to respond to the suggestion that I have made on a number of occasions that if they think it is possible to know when these things are going on we should have a specially staged arrangement under which one would take place at a specified time under a neutral umpire to see whether the Russians could spot the time and place when it occurred.