Defence Secretary Gavin Williamson has awarded a £235 million contract to Rolls Royce for the maintenance of nuclear engines used in the UK’s submarine fleet.

The deal includes the maintenance of engines in the Vanguard submarines which carry Britain’s Trident nuclear missiles.

The new contract will ring alarm bells with MPs after the Public Accounts Committee highlighted a £20 billion short fall in the Ministry of Defence budget last year.

Earlier this year, high-ranking officials in the Royal Navy and the MoD called into question the future of Trident.

Richard Scott from Jane’s said: “There is an understanding across the MoD and BAE Systems that they have continually failed to meet project milestones on Astute and need to do better.”

Mr Scott said that in private conversations with senior officials in the Royal Navy and the MoD, he now heard “comments about the disproportionate impact the deterrent has on the overall defence budget”.

“Some people are asking, ‘can we really justify this’?”