What recent assessment he has made of the financial sustainability of the Vanguard-class life extension programme.

The Vanguard-class life extension and availability sustainment programmes are essential to maintaining the United Kingdom’s continuous at-sea deterrence and are prioritised accordingly. The programmes are managed using established Ministry of Defence processes and, as such, are routinely reviewed.

April this year marks the 50th anniversary of continuous at-sea deterrence, and I pay tribute to the men and women of the submarine service for their dedication over those 50 years. Given the reported delays in the refurbishment programme of the Vanguard class, can the Secretary of State assure the House that CASD will be maintained into the future?

The right hon. Gentleman is right to pay tribute to the men and women, both past and present, who have done so much to maintain that at-sea nuclear deterrence. I can give him an absolute assurance that the investment and resources that are needed are being made available to maintain this important deterrence, which has always had a lot of cross-party support.

When my right hon. Friend considers the financial sustainability of the Vanguard programme, does he also consider the question of the nuclear doctrine? When was it last revised and on what basis would he reconsider revising it?

This is something that has to be continuously revised and looked at not just by our Department, but right across the Government, and that is always ongoing.

As the doyenne of British nuclear history, Lord Hennessy, observed recently, the current Vanguard life extension plans are a

“technological leap in the dark”,

which also means there is little room for flexibility in the overhaul and procurement cycle if CASD is to be maintained with two submarines in 2033-34. What discussions has the Secretary of State had in his Department about contingencies around the Vanguard-to-Dreadnought transition, which we know were discussed during the previous transition to Vanguard?

We constantly have discussions right across Government to make sure that our continuous at-sea nuclear deterrence can be sustained. We have been investing in technology and parts to make sure that the Vanguard class has everything it needs in the future. But what is critical is the investment we are making: we announced earlier this year an additional £400 million of investment in the Dreadnought class to make sure that is delivered on time and to budget.

But I am afraid to say that, as the misery of the modernising defence programme has shown all of us, the Secretary of State’s Department has much less latitude with large projects than he would like. With the nuclear project sucking up money, as he has just mentioned, from all other lines of spending, how long will it be before this overpriced nuclear weapons programme gets within sight of the Chief Secretary to the Treasury’s white elephant hunt across the Government?

When I look around this Chamber, I see many Members on both sides of the House who are absolute supporters of the importance of the continuous at-sea nuclear deterrent and understand how vital it is to keeping Britain safe. That unites both the main parties, and will continue to do so in the long term when we deliver Dreadnought.

Does the Secretary of State agree that Vanguard—and indeed Dreadnought, the next generation of our CASD programme—is probably the best weapon for peace the world has ever had? Will he update the House on plans to celebrate CASD’s 50th anniversary, which will be my birthday, too—we are almost twins?

I cannot imagine either CASD or my hon. Friend reaching 50, and I think we should put my hon. Friend on one of the submarines as part of that celebration. The anniversary shows that our nuclear deterrent has kept Britain, and also our NATO partners, safe over 50 years.

Several hon. Members:

rose—

Order. Before we proceed, I feel sure that colleagues throughout the House will wish to join me in extending this afternoon a very warm welcome to the Speaker of the Malaysian Parliament, Mohamad Ariff, whom I had the privilege of welcoming to the Speaker’s briefing meeting this morning—welcome to you, Sir, and to your colleagues—and a similarly warm and effusive welcome to the Speaker of the Australian House of Representatives, the right hon. Tony Smith. Sir, you are welcome; thank you for joining us and we wish you well in your important work.