HC Deb 15 February 1966 vol 724 cc1112-3
Q10. Mr. Alison

asked the Prime Minister if he will take a new initiative to secure the signing of a comprehensive treaty banning all nuclear tests, including those conducted underground.

The Prime Minister

The main obstacle to the conclusion of a comprehensive test ban treaty remains the impossibility, according to the best scientific advice available to us, of positively identifying underground nuclear tests by seismic means alone. The Russians claim that national means of detection are entirely adequate, and we have asked them to join in scientific talks to explore this claim. So far, they have refused.

Mr. Alison

Does the Prime Minister agree that the recent massive Soviet underground nuclear test, no less than other underground nuclear tests by other Powers recently, lends a new urgency to the problem? Does he appreciate that the conclusion of a comprehensive treaty would be a useful step in the direction of non-proliferation, and will he restore something of the energy of the last Government in pursuing this objective?

The Prime Minister

I agree about the urgency of this question of underground tests. The recent improvement internationally of means of detecting underground tests provides, I think, a more hopeful basis for getting this agreement. We agree that it is urgent. We agree that it is relevant to the question of non-proliferation, although not a substitute for a wider non-proliferation agreement. As to the sense of urgency shown by the last Government on this subject, they did, in the end, get a treaty.

Sir Knox Cunningham

Can the Prime Minister say whether there is any danger of contamination of the atmosphere from underground tests? Is that something that he can assure the House about?

The Prime Minister

I would like notice of that supplementary question but in general I think that the position is that there is no danger in the vast majority of underground tests. It was because of this that, three years ago, underground tests were separated from the rest. However, there have been one or two tests recently giving rise to some anxiety because of a certain amount of seepage following fall-out. I would not like to give 100 per cent. clearance. Perhaps the hon. and learned Gentleman will put down that Question.

Mr. Will Griffiths

Does my right hon. Friend expect to discuss this matter during his visit to Moscow?

The Prime Minister

Yes, Sir. I very much hope that we shall do so, together with the wider question of non-proliferation.

Mr. Hogg

Will the Prime Minister confirm that, should an underground test yield a substantial leakage into the atmosphere, it would be in breach of the existing partial Test-Ban Treaty?

The Prime Minister

Yes, Sir, I agree with the right hon. and learned Gentleman. But the hon. and learned Member for Antrim, South (Sir Knox Cunningham) asked whether underground tests could have the effect of contaminating the atmosphere. If a test did have such an effect, that would be a breach of the treaty. I would like to go further into the question, however, of whether this has been happening.