Defence secretary Phillip Hammond made the admission in response to a parliamentary question asked by Barrow and Furness MP John Woodcock.

There have been fears that the government’s Trident Alternative Review could recommend a further delay in bringing in new submarines, a move that would risk leaving a gap in the order book at Barrow shipyard.

The coalition government has already ordered a four-year delay to the in-service date of the successor deterrent boats, meaning that the existing Vanguard class vessels will have served for a record 35 years before they retire.

Following a question from Mr Woodcock in the House of Com mons, Mr Hammond confirmed the life of the hulls of the Vanguard submarine fleet cannot safely be extended beyond their latest retirement date, which for Vanguard – the oldest of the boats – is 2028.

Mr Hammond said: “We have already extended the life of the Vanguard class once and it is not judged possible or safe to extend it further.”

Speaking after receiving the response, Mr Woodcock said: “This clear view from the MoD that it would be unsafe to further extend the life of Vanguard should knock on the head any idea the government could put yet another delay into the build programme at Barrow.

“Aside from the extra cost and disruption that another delay would cause, we cannot countenance asking the sailors who bravely provide Britain’s nuclear deterrent to serve in life-expired, potentially unsafe hulls.

“By 2028, the Vanguards will have done good service, but the time will have come to provide the country’s vital deterrent with new submarines rather than spend huge amounts of money to extend the life of Vanguard still further, simply so we can again postpone the urgent decision on new boats.”

Source – North West Evening Mail