Dr Julian Lewis: I beg to move,

That this House has considered the matter of the nuclear deterrent.

The motion stands in my name, and that of the hon. Member for Newport West (Paul Flynn). Obtaining the debate involved a genuinely collaborative effort across the political divide. Part of the beauty of the Backbench Business Committee process is that it compels people who disagree profoundly about issues to work together to ensure that those issues are brought to the Floor of the House. No fewer than two dozen colleagues representing both sides of the argument supported our application for the debate at various stages.

They are too numerous to list, but representations were made to the Backbench Business Committee by – as well as the hon. Member for Newport West and me – the hon. Members for Islington North (Jeremy Corbyn) and for Brighton, Pavilion (Caroline Lucas), and my hon. Friends the Members for South East Cornwall (Sheryll Murray), for Crawley (Henry Smith), for Woking (Jonathan Lord), and for Wellingborough (Peter Bone). Others who were particularly supportive include the right hon. Member for Manchester, Gorton (Sir Gerald Kaufman), the hon. Member for Cambridge (Dr Julian Huppert), and my hon. Friends the Members for North Warwickshire (Dan Byles) and for Broxbourne (Charles Walker).

I know that several of those Members, as well as others – not least the former Defence Secretary, my right hon. Friend the Member for North Somerset (Dr Liam Fox), who is participating in a broadcast on this very subject this afternoon – regret that Committee meetings and other inescapable commitments prevent them from attending today’s debate. I am grateful to them all, and I hope that the tone and content of our debate between now and 5 pm will justify the effort that they all put into encouraging the Backbench Business Committee to select this important topic.

Given that we must fit some 20 speeches into just two hours, I shall endeavour to make my own remarks as brief as possible. I wish to outline just five military arguments and four rather more political arguments in favour of our retaining the independent deterrent.

The first of the military arguments is the most important argument of all: that future military threats and conflicts will be no more predictable than those that engulfed us throughout the 20th century. That is the overriding justification for preserving armed forces in peacetime as a national insurance policy. No one knows which enemies may confront us during the next 30 to 50 years – for that is the period that we are discussing, when the next generation of the nuclear deterrent will be in service – but it is highly probable that at least some of those enemies will be armed with weapons of mass destruction.

Henry Smith: I greatly regret that, owing to a prime ministerial meeting with GPs from my constituency, I shall be unable to take part substantively in the debate. Does my hon. Friend agree that our independent nuclear deterrent has helped to keep the peace in Europe for the past six decades, and that, because we effectively bankrupted the Soviet Union, it has led to the freeing of millions of people in eastern Europe?

Dr Lewis: I am sure that will be a central topic in our debate, and I entirely agree with my hon. Friend. I hope some of the later points in my list of nine arguments will serve to endorse what he has said.

My second argument is that it is not the weapons themselves that we have to fear, but the nature of the regimes that possess them. Whereas democracies are generally reluctant to use nuclear weapons against non-nuclear dictatorships – although they did so against Japan in 1945 – the reverse is not true. Let us consider what might have happened if in 1982 a non-nuclear Britain had been facing an Argentina in possession of even just a few tactical nuclear bombs and the means of delivering them. Would we then have dared to use our conventional forces against its inferior conventional forces?

The third military argument is that the United Kingdom has traditionally played a more important and decisive role in preserving freedom than other medium-sized democracies have been able, or willing, to do. Democratic countries without nuclear weapons have little choice but either to declare themselves neutral and hope for the best or to rely on the nuclear umbrella of their powerful allies. The UK is a nuclear power already and is also much harder to defeat by conventional means than many other democracies because of our physical separation from the Continent.

Paul Flynn: Is the hon. Gentleman arguing for every independent country in the world to possess nuclear weapons?

Dr Lewis: Absolutely not. I am saying that those countries that do not have nuclear weapons already often have other reasons that make it difficult to defend their borders, whereas, fortunately, we find it easier to do so because of our physical separation from the Continent.

The fourth argument is that our prominence as the principal ally of the United States, our strategic geographical position – to which I have just referred – and the fact that we are obviously the junior partner might tempt an aggressor to risk attacking us separately. Given the difficulties in overrunning the UK with conventional forces in comparison with our more vulnerable allies, an aggressor could be tempted to use one or more mass destruction weapons against us on the assumption that the United States would not respond on our behalf. Even if that assumption were false, the attacker would find out his mistake only when it was too late for all concerned. An independently controlled British nuclear deterrent massively reduces the prospect of such a fatal miscalculation.

The fifth of the military arguments is that no quantity of conventional forces can compensate for the military disadvantage that faces a non-nuclear country in a war against a nuclear-armed enemy. The atomic bombing of Japan is especially instructive – not only because the Emperor was forced to surrender, but also because of what might have happened under the reverse scenario. If Japan had developed atomic bombs in the summer of 1945 and the Allies had not, a conventional Allied invasion to end the war would have been out of the question.

Caroline Lucas: I want to follow on from the question from the hon. Member for Newport West (Paul Flynn) and press the hon. Member for New Forest East (Dr Lewis) on the logic of his argument. How can it be right for us to claim that we should have nuclear weapons, yet lecture every other country against trying to acquire them? If we are saying that the UK depends on nuclear weapons to be safe, does it not logically follow that every other country has the right to make the same argument?

Dr Lewis: The answer to that is catered for by the point I made earlier: it is not the weapons we have to fear but the nature of the regimes that have them. I have no desire to lecture other democracies on whether or not they should have nuclear weapons, as that is a question for them and it is about whether they feel they can afford to do that. It does not bother me if democracies have nuclear weapons, but I do reserve the right to lecture dictatorships, and preferably to try to thwart, baulk and deter them from having such weapons, because they are the threat, not the weapons themselves.

Mr Bernard Jenkin rose –

Dr Lewis: I will give way, but it will be for the last time as otherwise I will be in danger of taking too much time. [Interruption.] I thank my hon. Friend for his courtesy in resuming his seat.

I wish briefly to make four political points:

The first political argument is that when people are asked whether it is safer for this country to continue to possess nuclear weapons as long as other countries have them, a large majority of the population consistently take the view that we should do so and that it would be unwise and dangerous to renounce them unilaterally. We can ask different poll questions that seem to point to a different answer, but when that question is asked, the answer is surprisingly consistent.

The second political argument is that in the 1980s, under Cold War conditions, two general elections demonstrated the toxic effect of one-sided disarmament proposals on a party’s prospects of gaining power.

The third argument is that it was and remains widely believed – this refers to the intervention made by my hon. Friend the Member for Crawley (Henry Smith) a few moments ago – that the nuclear stalemate of the Cold War enabled all-out conflict between the majors powers to be avoided for 50 years, despite their mutual hostility and in contrast to what happened in those many regional theatres where Communists and their enemies could and did fight without fear of nuclear escalation.

The final political argument is that the ending of the east-west confrontation has not altered the balance of public opinion on this question. First, that is because a danger could easily re-emerge of a reversion to a confrontation of that sort. Secondly, it is because even today there are unpleasant regimes, such as Iran’s, on the point of acquiring nuclear weapons and some, such as North Korea’s, that have already done so.

The role of our strategic nuclear force remains what it has always been: to deter any power armed with mass destruction weapons from using them against us, in the belief, true or false, that nobody would retaliate on our behalf. The use of our deterrent consists of its preventative effect on the behaviour of our enemies. The actual launching of a Trident missile would mark the failure of deterrence and would presuppose that a devastating attack had already been inflicted on our country.

Because strategic nuclear deterrence is largely irrelevant to the current counter-insurgency campaigns with which the British Army has been involved, some senior Army officers have been suggesting that we must choose between fighting “the war” of the present and insuring against the more conventional prospect of state-versus-state conflict in the future. I say that that choice is unacceptable, and that the underlying message that the era of high-intensity, state-on-state warfare is gone for good is a dangerous fallacy.

Every sane individual hopes that such warfare will never return, but to rely on that in the face of past experience would be extremely foolhardy. The lesson of warfare in the 20th century, repeated time and again, was that when conflicts broke out they usually took their victims by surprise. Obvious examples are: the failure to anticipate the First World War; the follies of the “10-year rule” from 1919 to 1932; and the entirely unanticipated attacks on Israel in 1973, the Falklands in 1982, Kuwait in 1990 and the United States in 2001. Conversely, and on a brighter note, the speed with which the Soviet empire unravelled from 1989 left even its sternest critics largely nonplussed.

Jeremy Corbyn: Will the hon. Gentleman give way?

Dr Lewis: I will not, because I am about to finish. I hope the hon. Gentleman will forgive me.

Our current counter-insurgency campaigns are very important indeed, but they cannot be compared with battles for the very survival of the United Kingdom homeland. Such existential threats confronted us twice in the past 100 years and, if international relations deteriorate, they could easily confront us again.

My final remark concerns the alternatives. I can see only three possible alternatives to renewing Trident other than getting rid of the nuclear deterrent completely. The first is that suggested by the Liberal Democrats of putting cruise missiles on Astute-class submarines. I have said in the past and say again that that would be more expensive and less effective, would put the submarine at risk because of the shorter range of the missiles, which would bring the submarine closer to shore, and could start World War Three by accident because no one would be sure whether the launched missile had a conventional or nuclear warhead. Apart from that, it is a great idea.

The second alternative is to come off continuous at sea deterrence, to put the nuclear deterrent on stand-by and to say that we will reactivate it if things get worse. That is an extremely dangerous suggestion, as having a part-time deterrent is probably as dangerous as, if not more dangerous than, having no deterrent at all.

The final suggestion is that we could perhaps combine our deterrent with that of the French and therefore have fewer submarines. All I can say about that is that our deterrent is strongly connected with the excellent working relationship we have with the United States, which would not admit of such a solution.

I hope that I have given people plenty of food for thought. We have an hour and three-quarters left and I very much look forward to hearing both sides of the argument in the time that remains.

[For the text of the full debate, including the Front Bench contributions, click here. One particularly appreciated remark was that of former Labour Chief Whip (and opponent of Trident) Nick Brown:

Mr Nicholas Brown: It is a pleasure to make a very short contribution to the debate. I congratulate the hon. Member for New Forest East (Dr Lewis) not only on having secured it, which is a triumph in itself, but on how he argued the case for Britain’s independent nuclear submarine-based deterrent. It was the strongest series of arguments that I have heard made in one place for the renewal of the Trident platform. I do not agree with those arguments, but they were strongly made and the hon. Gentleman drew together all the different points that can be made.]