Dr Julian Lewis: Exactly 12 months ago, the MOD rather bravely published a document entitled, "The Future Strategic Context for Defence". In its introduction, it set out the problems with future thinking of that type:

"We recognise that the paper will contain judgements about the future with which many will disagree. Inevitably events will prove some of our judgements to have been wrong (perhaps this is the only truly certain prediction which we can make).

"The nature of such analysis tends not to identify the possibility of 'shocks', low-probability events with a dramatic effect ... It is in particular the potential negative impact of shocks that we need to be aware of for purposes of contingency planning. Across a 30-year period we must expect a number of such shocks, even if we can't predict their nature, which have the potential fundamentally to disrupt our carefully laid plans."

Those were indeed prophetic words because, not 30 years hence but only one year hence, here we are discussing primarily the aftermath of a particular shock: the events on 11 September last year.

We had sight for a rather brief period before the commencement of the debate of a new consultation document on how the strategic defence review should be updated in the aftermath of that atrocity – that outrageous mass murder that was nothing short of a declaration of war on the West. The document, which I have seen today for the first time, asks us to make our views known on no fewer than 11 different points. The questions are set out in a useful summary. In the limited time that I intend to confine myself to, I shall work my way through as many of them as possible; so I may not give the most comprehensive response to the document that the MOD will receive, but I pride myself on giving the first response to it.

The first question is:

"What should the international community do to address the key underlying causes of international terrorism? What specifically should the UK aim to do?"

There will always be a minority of fanatics in any society, no matter how liberal, civilised and enlightened, who are prepared to engage in totalitarian, murderous activities. The aim of that civilised society must be to keep them away from the levers of power. In particular, the elements that lead to terrorist events are the existence of such fanatics, their access to weapons and the availability to them of a protected base, usually supplied by a host country. When asked what we must do about that, I say in brief that we must identify, infiltrate and monitor such organisations, actively impede their acquisition of weapons and recover those that they have already managed to acquire, and destroy their bases, if necessary overthrowing the regimes that harbour those bases and decline to close them.

The second question is:

"In the medium to long term, what balance should the UK seek to strike between contributing Armed Forces, on the one hand, to help address the symptoms of terrorism and, on the other, to assist in efforts to address the causes of terrorism?"

The symptoms that we may have to face in this country are three. The first, which has not materialised anywhere yet, is small-scale suicide terrorism carried out in large quantities. That was what I feared we would be facing early on when we met on 14 September for an emergency sitting. I contributed to that debate and talked about the grave and severe changes that there would have to be in national life to cope with that sort of threat.

So far, it appears, a few spectaculars rather than a large number of low-level operations have been planned. Large-scale, spectacular attacks on public buildings are the second category about which we must be concerned. The third, which has been alluded to briefly, is mass attacks on the civil population using methods such as those that Soviet spetznaz forces were discovered to have formulated in the early 1970s for use in the event of a war on this country. Hon. Members will remember from their history that that led to the expulsion of more than 100 so-called Soviet diplomats – a coup from which the Soviet intelligence service in this country never recovered.

On assessing the likelihood of such threats being carried out, I am grateful to a friend for drawing my attention to an article in the Mail on Sunday on 3 February, which purported to be an interview with someone out in Lahore near what was alleged to be an al-Qaeda training camp. He claimed to have been born in Britain, to have worked as a doctor in Britain and to retain British nationality.

That person, who used the name 'Dr Hakani', said:

"Our work has hardly started. America is still bombing Afghanistan, now we want to bring the war to Britain and America. We are waiting for the right time to return to our sleeper cells in the West and launch full-scale attacks.

"Unlike America, we do not want to harm civilians."

Tell that to the bereaved of the World Trade Centre victims. He continued:

"We will be hitting public buildings, government and military targets and leading politicians like Tony Blair. All of us who have fought with Al-Qaeda would welcome martyrdom. We can see spectacular results from another September 11. We could hit Tower Bridge, Buckingham Palace or the Houses of Parliament."

That threat is obviously worrying, but at least it is small in terms of the numbers involved. If it remains as such, we are much more likely to be able to prevent it from being carried out. Let us remember this: at first, we were unsure of the extent to which the UK Muslim community might be a source for terrorists, but it now appears that it is barely a source, as the numbers involved are very small. We must consider using the UK Muslim community, with its consent, as a resource against terrorists.

In that connection, I cite the experience of the Jewish community. Since being allowed to develop at the turn of the last century, which is when my grandparents came here, it has played a full part in the defence of this country. Hon. Members with knowledge of military history will have been reminded of that by the recent death of Tommy Gould VC, the famous submariner.

I have already mentioned the major causes – the coincidence of the existence of terrorists and their ability to get their hands on weapons while enjoying a secure base – and we can no longer ignore the behaviour of dictatorial regimes that are determinedly pursuing the acquisition of weapons of mass destruction. We must be careful of again burying our heads in the sand and saying, "Saddam Hussein may be acquiring nuclear, chemical or biological weapons of mass destruction for all we know." We do not know whether he has such weapons because he did not allow the inspection demanded by the international community.

We must not say, "We will deal with this as and when it manifests itself." We must not wait; and if regimes are trying to acquire such weapons, it is up to us to stop them doing so, having given them every opportunity to allow the inspections which would show that they are not engaged in such activity. We must not allow the clock to tick indefinitely, as we may eventually find that the ticking is that of a time-bomb.

The third item on the list to which we have been asked to respond bears on what I have said:

"How should we strike a balance between the defence role in helping to protect the UK, and contributing to operations against international terrorists and other asymmetric threats overseas?"

I believe that that is one of those occasions when the author of the document posing a question has answered it in the body of the document far more effectively than anyone else could. Thus, before I conclude, I wish to put on the record paragraph 27, which appears on page 7 and states:

"it is usually better to seek to engage an enemy at longer range – before they are able to mount an assault on our interests. Not only is this more effective than waiting to be attacked at a point and timing of an enemy's choice, it can have a deterrent effect. We must therefore continue to be ready and willing to deploy significant forces overseas to act against terrorists and those who harbour them."

The document recommends a combination of prevention, deterrence, coercion, disruption and destruction, applicable in different degrees to different targets.

We can try to prevent terrorism by putting pressure on Governments willing to harbour terrorists to ensure that they no longer do so. We can try to deter terrorism by showing that those who wish to harbour terrorists, or to sympathise with them, will meet not a feeble response from the west, but a massive one.

We can try to coerce host regimes to ensure that they do not think that they can wage a sort of proxy warfare. That possibility resembles what happened in the cold war, when people who did not want to fight the west openly would push smaller, so-called client states to wage guerrilla war on their behalf. If Afghanistan has taught people of that mindset anything, it should be that that approach will not work in this case.

Disruption can be of only limited effectiveness against specific operations. In the end, terrorism has to be destroyed, without mercy or limit, wherever it rears its head in the world. That is why we must not close our eyes to the fact that ruthless regimes exist that for years have sought to acquire weapons which, even if they did not want to use them themselves, they could pass to other groups that would have no compunction about doing so.

I am not sure that the Conservative Government of the time did themselves any favours when they left Saddam Hussein in power at the end of the Gulf war. The time may be coming to put right that mistake. If it is necessary for us to act, we must do so firmly, and in a way that means that we will never again see anything as terrible as what happened so disastrously on 11 September.