Dr Julian Lewis: Given that both the Polaris and Trident submarines came in on budget and on time, is that not a good precedent for the successor system? Will the Minister take the opportunity to repeat in resounding terms the assurance that the Prime Minister gave to Conservative MPs when the coalition was formed – that Trident will be renewed, whether the Liberal Democrats like it or not?

[The Parliamentary Under-Secretary of State for Defence (Peter Luff): I believe that, notwithstanding the views of the hon. Member for Islington North (Jeremy Corbyn), no programme is subject to greater scrutiny in the House than the nuclear deterrent. That is one of the reasons for the accuracy of our costings. Let me assure my hon. Friend that the primary responsibility for our nation is the security of the country, that the nuclear deterrent is the ultimate guarantee of the country's security, and that we stand firmly behind it.]