Dr Julian Lewis: It is a pleasure to contribute to this debate under your chairmanship, Ms McDonagh, and to follow the hon. Member for Plymouth, Sutton and Devonport (Luke Pollard), who has done a service – not for the first time – to the House of Commons, by bringing key defence issues for our consideration.

Having said that, I am going gently to disagree with the hon. Gentleman. I did not know what line he was going to take until I heard his speech this afternoon and I shall be a little heretical myself, because there is a track record on this question of what we ought to do in terms of designing replacement frigates, particularly lighter replacement frigates.

The context in which one wishes to set this is the relentless decline in the size of the frigate and destroyer fleet. The House will probably not need reminding that we had more than 60 frigates and destroyers at the time of the Falklands campaign. By the time that my cohort came into the House of Commons in 1997, that number had come down to 35 frigates and destroyers.

The incoming Blair Government conducted the strategic defence review of 1997-98. That was where the twin concepts of the carrier strike force and the amphibious force making up the sea base, which would be able to exert land and air power from the sea in any particular theatre of warfare across the globe, was born. As a price ​for bringing forward the idea of the two super carriers, a modest cut in the number of frigates and destroyers was put forward, from 35 to 32 vessels. We all know what happened next: the 32 came down to 31; the 31 came down to 25; and the 25 then came down to the present woefully inadequate total of 19. That is the issue that the hon. Gentleman quite rightly wishes to address. If there had not been any changes in the method of warship design, I would have signed up entirely to his argument from beginning to end.

But the one factor that I wish people to take away from my contribution to this debate is the concept of a template warship. The phrase “modular build” is the one that we need to keep in mind.

I talked about the way in which the numbers of frigates and destroyers were reduced. Part of that process was the way we went about replacing the destroyer fleet. At the time we started introducing the Type 45 we were down to 12 destroyers, and the original idea was that those 12 destroyers would be replaced with 12 Type 45 destroyers. We know what happened then: the same process – the 12 went down to eight, and eventually we ended up with six. Why did that happen? It happened because of our insistence, and the Royal Navy’s understandable concern, that the new warships should be top of the range, ab initio, in every respect that can be thought of. When we do that and we keep adding, in the long course of a period of design and build, more and more requirements to a new warship, inevitably the price goes up and the number of units we can afford to build comes down.

I was fortunate enough to see the Type 45 destroyers close up at a very early stage. Being taken on a tour of the ship, I was struck by the fact that a very large area in the forward part of the ship was devoted to the ship’s gymnasium. Why did the Type 45 destroyer have such a large gymnasium? The answer I was told was that the space that was going to serve as a very large gymnasium was earmarked for the future, so that when we could afford to add a suite of tactical Tomahawk cruise missiles – surface-to-surface, long-range missiles, which we could not afford to equip the Type 45 destroyers with at the time – we would be able to remove the paraphernalia of the gymnasium and insert a module into that area, thus installing this massive upgrade in the weapons system at some future stage in the ship’s life. Warships are rightly designed to have a long lifespan; we are told that the new carriers, for example, are meant to last us for the next 50 years. So how much better is it – the answer is hugely better – to design them from the outset so that instead of having to rip the ship apart halfway through its life to upgrade it, we can easily add to its capacity?

In 2009, I published an article that got me into a lot of trouble. In the RUSI Defence Systems journal in February 2009, I said what was perhaps the unsayable: that if we were ever going to get the future frigate fleet back up to the sort of numbers we needed, we would have to design it in such a way that it was as “cheap as chips”. The First Sea Lord of the day, Admiral Sir Jonathon Band, who is a great man, was not at all happy with that phrase. But I did not use the phrase lightly; I used it because now we have this technique of plug-and-play, of modular build. If we could design a template warship that had all sorts of empty compartments in it from ​the outset, and if we could get a large number of hulls into the water from the outset, by a process of incremental acquisition, we could arm them up so that, over a period of years, they would become more and more capable.

I see the hon. Member for Plymouth, Sutton and Devonport nodding as a sign, I hope, of some approval of the line that I am taking. We are not disagreeing about ends; we are slightly disagreeing about means. I do not wish to see the Type 31e become more and more expensive before even the first one has been completed. I wish to see a hull design – I look to the Minister to tell us how that is progressing – that will enable us to maximise the number of hulls and to spread the cost of a really high-capability warship, which the hon. Gentleman rightly wants to see and I want to see at the end of the process, over a longer period of years. That is so that, when the defence budget gets the uplift that it needs – and we all hope it will if the Secretary of State for Defence is successful in his so far heroic but incomplete campaign to take on the Treasury – we can hope to start to reverse the terrible downward spiral in the number of frigates and destroyers that had rendered our fleet incapable of doing its duty. The Royal Navy, as we know, is very strong on doing its duty, and we need to give it the tools and the warships to finish that job, whatever job it is confronted with in the uncertain future.