Since I first intervened, in a maiden speech, on defence matters 23 years ago there has been one consistent theme in all the White Papers on defence which have been published. It is the one summarised in paragraph 4 of the white paper, which issues a grim warning about the growing extent in real and relative terms of Soviet power.

In the early days, going back to the years after the war, when the allies had an overwhelming preponderance and a monopoly of the atom bomb, this was taken fairly lightly. But those days have long since passed away. A comparison of the warnings given in paragraph 4 of the White Paper, rightly drawing attention to the growing size of the Soviet operation, with the other side of the picture and the generally accepted belief that the Americans in one way or another will phase themselves out of Europe, perhaps slowly—but there is little doubt that they will start doing it—and the fact that the French are still outside NATO, and bearing in mind what my hon. Friend the Member for Aldershot (Mr. Critchley) said about the Germans having both the economic power and the manpower to make an effective contribution but being too riddled with a sense of guilt for what happened in the last two wars to be the effective ally that one might otherwise expect, shows that the forces ranged against the Soviet bloc are pretty fragile.

I wonder whether we are building up forces appropriate to today's conditions. Basil Liddell Hart, an old personal friend of mine, used to say over and over again that we fight the next war on the text books of the last. Even with all those lessons in mind, I believe that we are still in danger of repeating that error.

Many people thought after the last war that the proliferation of atomic power, when it ceased to be an American monopoly, spelt a speedy end to civilisation. In the event they were proved wrong. The balance of terror—that grim phrase —precarious as it was, actually worked. We have had a long period not of peace but a period during which the likelihood of the outbreak of an atomic war has steadily receded, although there have been times such as the Cuban crisis when it was perilously near. We all remember the days of the nuclear disarmers, the marches, the demonstrations and the sentiments reflected in this House. All is quiet on that front now because the sheer credibility of either side taking the risk of nuclear war has subsided.

So it was that the emphasis for some years past has switched increasingly to conventional forces and to more sophisticated but still on the whole non-nuclear weapons. This new emphasis has become apparent in the forces mentioned in the White Paper. But I still wonder whether we are not preparing for the wrong kind of aggression still with our basically conventional navies, armies and air forces. I believe that we are already witnessing the kind of warfare that we should be preparing for, if warfare it has to be. Certainly it will not be nuclear. There will be no armies marching, no aircraft bombing and no navies confronting one another on the high seas.

I believe that we have had a foretaste of the form that the aggression might take, with the aircraft hijacker, the kidnapper and the small group of utterly ruthless men like the Black Septemberists armed with modern weapons and without scruples. Such people have already held whole Governments to ransom to secure their ends. I believe that this process is only in its infancy.

It is the sophistication of weaponry today which places such appalling power in people's hands. The ease with which incredibly small and devastating devices can be manufactured quite cheaply places a frightening concentration of power into a very few desperate hands. Skilfully used, this power can blackmail Governments and hold whole populations in terror. It can effectively overturn key sectors of industry and paralyse communications if it is applied ruthlessly at the right point and at the right time.

In such circumstances conventional armies, navies and air forces are not relevant. That is not an argument for not having conventional forces. It is one for developing them in such a way that there is a conscious and deliberate provision to deal with this kind of armed subversion. When the damage is done and when the citadel has fallen, it is no use mobilising the army, sending in a gunboat, turning out the air force and the rest. It is too late.

I do not see anywhere in the Defence White Paper, which otherwise I welcome, even a recognition of this new dimension of war, let alone any special measures to deal with it. It is no good saying that this is a police operation. It is too big and too dangerous for the police to tackle unaided. We have had a glimpse of it in a relatively primitive form in Ulster. There we have seen how 20,000 soldiers have been pinned down for months. That is a measurable part of our entire establishment coping with this sort of guerrilla subversion. Let no one dismiss it and say that it is a police operation and not one for the Armed Forces. It is not.

Over the years civil defence has been dismantled. But there might have been a nucleus of trained manpower there who would have been appropriate to deal with this threat.

When all is said and done, the defence of the realm is at risk. In all the millions of pounds that we spend we should spare some money urgently to carry out some research and make some provision to meet the growing threat of urban guerrilla subversion and armed activity. I remember my hon. and gallant Friend the Member for Aberdeenshire, West (Lt.-Col. Colin Mitchell) making a very good speech about this in an earlier defence debate. No one can say that I am breaking new ground. However, I should like to hear the Minister say that he is breaking new ground in making provisions to counter this real and desperate threat.

I do not profess to know the answer myself, but the problem must be known to our defence chiefs and must be appreciated by them. We know that our reserves are limited. That is why when they are deployed they should be deployed in the right way. Whatever form the next war takes—and it will not be a conventional kind of war—there will be no use in re-fighting El Alamein and Midway or re-invading the Continent. None of those matters will be relevant. The trouble will come from within. It will be quick, ruthless, and devastating. I want to see suitable provision in the Defence Estimates. The requirement may be for a special corps of people. I do not know the answer. The defence chiefs must be thinking about the matter, and I hope that my right hon. Friend, when he replies, will be able to give some reassurance.