HC Deb 26 March 1984 vol 57 cc12-5W
Mr. Lawrence

asked the Secretary of State for the Home Department what action he proposes to take to meet criticisms made of the accuracy of the Lion Intoximeter 3000 breath-testing machine; and if he will make a statement.

Mr. Hurd

We have carefully examined these criticisms. The aim must be to ensure beyond doubt that any mistake of malfunctioning of a particular machine is either identified by the machine itself or by the operator, so that no action is taken against an individual based on that mistake.

The doubts expressed about breath-testing machines as a reliable source of evidence in drink-driving cases are of three kinds. These relate to the provision of breath to the machine; the testing of the breath sample for alcohol content; and the conduct of police procedures in operating the machine.

As to the provision of breath, some people refuse to provide a breath sample or deliberately make no real attempt to provide one. The genuineness of any attempt is a matter of judgment for the police operator and this is, of course, subject to challenge in court. It has been suggested that in other cases some people have had difficulty in blowing a sufficient quantity of breath into the machine and later been convicted unjustly for "failure to provide". There have been occasions — a notable example being the recent one in Carlisle — when a machine has developed a particular kind of mechanical fault which has the result that even a fully fit person cannot get sufficient breath into it. The offence at issue in this category of case is one of failure to provide without reasonable excuse. No one should be prosecuted for this offence when what took place was due to a mechanical fault; and such a fault should be obvious to the police operator.

As to the testing of the breath sample for alcohol content, it has been said that the machines can give a false reading of the amount of alcohol in the breath. The evidence in our possession suggests that this is not a valid criticism. Before their introduction the machines were subjected to field trials which proved their general accuracy by comparing their results with blood samples. Since then, a further survey has been undertaken by the forensic science service. A report of this survey has recently been produced and a copy of it has now been placed in the Library. It shows that, in the 620 cases examined, blood samples confirmed the accuracy of the results shown by the breath-testing machines. After the necessary allowance was made for alcohol eliminated from the body naturally during the sobering-up period between the taking of the breath and blood samples there was no case in which the result of the blood test pointed to an inaccurate breath machine.

As to police procedures, it has been suggested that these may be at fault. Human error is always possible in particular cases, despite the steps taken in both the designing of the machine and in the guidance to and training of police operators to limit this possibility. Machines contain their own calibration checking procedures which are automatically operated both before and after every single breath test and the results are printed out along with the result of the breath test itself and are thus available as evidence in court. It is the responsibility of the police operator to make sure that the results of the automatic calibration checks are satisfactory. I am aware of one case where the result of the automatic calibration check displayed on the print-out was not correctly spotted. The guidance which has been given to police officers about operating procedures is being reiterated and expanded. If the operating procedures are followed properly and fairly in all cases the machine itself need not give rise to an injustice.

These breath-testing machines have substantial safety margins, and where a breath test shows a result near to the legal limit of alcohol content in the breath—that is, within the range 35 to 50 microgrammes per 100 millilitres of breath — there is a statutory right to a blood/urine test. The machines have enabled an essential part of the road safety law to be enforced more simply and the police to cope with a larger number of offenders than if we had continued with the old and somewhat cumbersome procedures. Drunken driving is a serious menace to the public, and we need to have the most effective means available to deal with it.

We recognise that if the benefits which we have derived from the machines are to continue public confidence in them is essential. This has suffered as a result of recent publicity and there is a need to re-establish confidence.

We therefore propose with the co-operation of the police that for a period of six months anyone who gives a breath test result which is above the present 35 to 50 microgrammes range should also have the option of a blood/urine test. For that period the blood/urine test option will not be restricted as it is now to persons whose breath alcohol reading on the machine is 50 microgrammes or below; it will also be available as a matter of administrative practice to those whose breath test reading shows a level of above 50 microgrammes per 100 millilitres of breath. They will be told by the police that they can ask for a blood/urine sample to be taken, and in these cases both the certificate of analysis of the blood/urine sample and the print-out of the breath-testing machine will be available as evidence.

The results of all cases where the blood/urine test option is exercised will be closely monitored by the forensic science service and a report of the results will be published at the end of the monitoring period. The six-month period will start from 0001 hours on 16 April. The time between now and then is needed so that the police can prepare to operate the new system in a fair and uniform way and the magistrates courts can be fully informed of the procedures which the police will adopt. From 16 April onwards the blood/urine test option will be available on the extended basis which I have described. Before then all cases will be dealt with under the present statutory arrangements which restrict the blood/urine test option to marginal cases.

Although four English police forces use a different machine from that which has been the subject of recent publicity, the new arrangements which I have described will apply throughout England and Wales. My right hon. Friend the Secretary of State for Scotland is considering the different position in Scotland, where no use is made of the Lion Intoximeter 3000.

Mr. Fisher

asked the Secretary of State for the Home Department what were the precise faults developed by the defective Lion Intoximeter 3000 withdrawn from the field trials prior to its introduction; and if he will make a statement.

Mr. Hurd

The Lion Intoximeter 3000 withdrawn from the field trials was found to have had an assembly fault which caused it to give unreliable readings as to the acetone and alcohol content of the breath samples being analysed. The exact nature of the faulty readings is described on page 5 of the report of the field trials prepared by the Department and is available in the Library of the House.

The instruments used in the field trials were manufactured in the USA and were not subject to the tests and certification procedures administered by the British calibration service which are applied to all instruments manufactured in this country.

Mr. Fisher

asked the Secretary of State for the Home Department whether he will amend the report of the field trials on the Lion Intoximeter 3000 to include the results of the instrument which was found to be faulty and was subsequently replaced.

Mr. Hurd

It would not be practicable to amend the text of a report which has been widely circulated through HMSO, but I shall place in the Library of the House a note setting out the results requested.

Mr. Fisher

asked the Secretary of State for the Home Department what information he has as to the number of police forces which have reviewed cases since May 1983 involving the Lion Intoximeter 3000; and whether he will list them with the number of cases so reviewed.

Mr. Hurd

Cumbria constabulary and the Metropolitan police are reviewing cases arising from one Lion Intoximeter 3000 in each force. Staffordshire police are reviewing cases to ensure that standard operating procedures have been complied with. I refer the hon. Member to the reply I gave to him on 8 March, at column658. Details of the number of cases so reviewed are not available at present.

Mr. Fisher

asked the Secretary of State for the Home Department at what stage of the field trial on the Lion Intoximeter 3000 one of the four instruments was replaced; and by what means the results obtained from the replacement instrument were incorporated in the final report.

Mr. Hurd

The fault in the instrument in question was detected at the end of the first six-week period of trials and the instrument was withdrawn straightaway. The rest of the trials were conducted with another instrument, the results of which are incorporated in the evaluation set out in the report prepared by the Department.

Mr. Lawrence

asked the Secretary of State for the Home Department if he will make available to the House the findings of the forensic science service survey of results from the Lion Intoximeter 3000.

Mr. Hurd

There is provision in the legislation for subjects with a breath alcohol reading of not more than 50 microgrammes/100 millilitres to provide a blood/urine sample if they so wish.

The forensic science service has collected data in 620 cases from seven police forces where subjects had a breath reading at or above the prosecution level of 40 microgrammes and who exercised the blood option. The legal limit is 35 microgrammes.

In 497 of these cases the certificate of analysis showed the blood also to be above the prescribed limit.

In all cases the breath and blood samples were provided at different times.

If allowance is made for the loss of alcohol, which occurs naturally, during the interval between the provision of the breath and blood samples all the remaining 123 cases would have had blood analyses above the prescribed limit; 17 cases would not have been proceeded with because, although above the prescribed limit, they were below the effective prosecution level of 87 milligrammes of acicohol/100 millilitres of blood.