The right hon. Member for Blaenau Gwent (Mr. Foot) in a sense demeaned himself by suggesting that the Government have gone down this path solely because they are interested in money. That lowered the level of the debate to a deplorable standard.

This is an issue of the utmost importance, and there are sound and considerable reasons why a view may be taken on whether the right hon. Gentleman's argument is right or wrong. However, I am sure that money is not one of the reasons.

In that context, the Marshall Institute of the United States—a very respectable and independent organisation —in response to the question, Does SDI violate the ABM Treaty?said:SDI is a research program whose stated goal is research on ABM defenses. However, the ABM Treaty does not limit goals. It only limits certain activities. The Department of Defense experiment that successfully demonstrated the 'smart bullet' concept at Kwajalein last June was in accord with the ABM Treaty because the Treaty allows ABM tests from areas specified as missile test ranges and so designated by the parties. (Article III.) The United States has designated Kwajalein as a missile test range. The Marshall Institute concludes—this is relevant to the argument of the right hon. Member for Blaenau Gwent: We may bump up against the Treaty in three or four years —if, for example, we begin to test space-based components. But for the next several years there is no conflict between SDI and the ABM Treaty. The Soviet 'Star Wars' program will also bump up against the ABM Treaty soon. Some experts say it has already done so. That is the answer to the right hon. Member for Blaenau Gwent.

There is an exception to almost every rule in life, and on this occasion I am happy to be able to say that I welcome the Leader of the Opposition's choice of subject for debate. Instead of the usual "Who done what and when" saga, we have an opportunity—alas, all too brief —to debate what is to my mind the most important decision facing the West today. Indeed, it faces both super-powers, because I also take the view that a fundamental Western interest is the survival of the Russian people as a whole long enough for them to understand, evaluate and eventually escape from the yoke of their self-imposed tyranny. That is in the interests of the civilised world.

The perspective of this decision on SDI on both sides extends well into the next century and clearly embraces that possibility. Our purpose is not merely the survival, but ultimately the legitimate enlargement, of the free world by the voluntary actions of convinced peoples.

The decision is not ours to make. It has been made by the United States, and inevitably our decision is merely one of participation. But it is important that both should be right and fully justified. Both are decisions not only of greater importance but also of greater complexity than any which this House has addressed for many years. It is quite ludicrous that we should devote a mere three hours to a subject that could well justify a two-day debate. Once again our priorities reflect the lamentable unwillingness of this House to involve itself in scientific and technological decisions of great moment, partly because we do not understand them, and partly because we are so badly briefed.

Virtually all the briefing of any weight or consequence is, alas, American. There has been much discussion, but most of that—until General Abrahamson arrived in the United Kingdom this weekend — has been in the technical press. I have with me—it is a document that I commend to the House as an outstanding example of technical briefing— the report on anti-satellite weapons and counter-measures and arms control prepared for the United States Congress by the OTA. It is both a formidable and formidably important analysis, and there is one conclusion to which I draw the attention of the House.

After examining the seven major policy options—not just the one to which the right hon. Member for Blaenau Gwent referred—the OTA concluded: The opportunities and risks that might result from developing or not developing ASAT weapons or from pursuing or not pursuing ASAT arms control cannot be simply stated … the choices will require a delicate balancing of strategic economic and political interests. Reasonable persons can and will disagree as to the most appropriate nature of this balance. That is a central conclusion to this debate. I support the objective and the programme, but I have serious reservations, some of them technical and some political.

My technical reservations are based fundamentally on what are known as the Parnas memoranda. Professor Parnas, who resigned from the SDI software panel, has in a series of formidably powerful papers argued that neither the software nor the hardware will prove sufficiently powerful, reliable or effective. His case is that the goal is unattainable.

I have seen no really convincing or persuasive reply to those memoranda. I should like to see such a reply, because nothing is more damaging to the reputation of science or technology, be it in the military or any other sphere, than attaching to it a series of expectations that are thought to be wildly unrealistic. We should reflect for a moment on what the computer system has to do.