Royal Navy submarine HMS Victorious departing from HMNB Clyde (Library picture: MoD).
The infrastructure for supporting the Royal Navy's fleet of nuclear submarines is no longer "fit for purpose", MPs have warned.
The Commons Public Accounts Committee said past decisions to delay maintenance at the Ministry of Defence's (MoD) 13 nuclear sites around the UK had created a "ticking time bomb".
The warning came after the National Audit Office disclosed earlier this year that the MoD's 'Nuclear Enterprise' programme was facing a £2.9 billion "affordability gap".
The Committee Chair Meg Hillier said that with the MoD already facing "challenges" over the delivery of its new aircraft carriers and a potential £20 billion shortfall in its equipment programme, there were "serious questions" over its ability to meet its national security commitments.
Forces News asked her what poses the biggest risk to UK security and Britain's ability to defend itself:
Over the next 10 years, the MoD is expected to spend £51 billion on the Nuclear Enterprise - maintaining and replacing the submarine fleet, including the Vanguard submarines which carry the UK's Trident nuclear deterrent.
However, the committee warned "incorrect" assumptions in the past about the infrastructure that would be needed meant it did not have the berthing space it needed at the Devonport naval base where maintenance and "defuelling" of the submarines is carried out.
It said the MoD had deferred work on dismantling old submarines which had been taken out of service on "affordability grounds" and there was now a backlog of 20 vessels waiting to be disposed of, including nine which still contained nuclear fuel.
An MoD spokesperson said: “Our nuclear programmes are some of the most complex engineering projects ever undertaken by the UK defence industry. They provide the most powerful submarines in our history and support thousands of British jobs.
“We are committed to delivering these nuclear programmes on time and within budget and will carefully consider the recommendations in this report to ensure this remains the case.
“We continue to press ahead with our dismantling projects. Work is underway to enhance our infrastructure so our programmes continue to run at the highest standards.”
To date, the UK has never completely disposed of an old nuclear submarine and while work has begun on the first, it is not due to be finished until the mid-2020s.
The committee said work on defuelling the next submarine was due to begin around the same time, and that the disposals programme was expected to last "at least a couple of decades".
Ms Hillier said:
"I am particularly concerned that the infrastructure available to support the Nuclear Enterprise is not fit for purpose.
"The MoD admits that while it has previously put off dismantling submarines on grounds of cost, this is no longer acceptable on grounds of safety and reputation. The MoD needs to get on top of this quickly."