The operational life extension of the Trident missile-armed nuclear submarine could cost the UK $2.3bn, Defence Secretary Liam Fox has said.
"There will be additional costs to maintaining the Vanguard Class through to 2028," he admitted.
According to the UK policy of continuous-at-sea-deterrence, the operational life of the aging strategic submarines would be extended.
The revised plan meant that the current Vanguard vessels would retire in 2028 rather than 2024, according to Global Security Newswire.
A cost efficiency analysis of the Trident plan, however, did not reach the estimated $1.9bn to $2.3bn in added costs from extending the sea life to 2028 of the current submarine fleet.
UK Prime Minister David Cameron, in the Strategic Defence and Security Review, published last month, said a final decision on replacing each of the four Vanguard Class submarines has been postponed until 2016.