The Ministry of Defence denied today it had agreed to spend £3 billion on new nuclear warheads, despite documents revealing a senior official told the arms industry a decision had already been made.

According to the 2006 White Paper on the future of the country's nuclear deterrent, any decision on whether to replace the warheads will not be made until the next Parliament.

But documents released to the Guardian following a Freedom of Information request revealed comments made by David Gould, the then-chief operating officer at the Defence Equipment and Support Organisation, stating the warheads would be replaced. The newspaper reports Mr Gould said: "This afternoon we are going to outline our plan to maintain the UK's nuclear deterrent.

"The intention is to replace the entire Vanguard class submarine system. Including the warhead and missile."

His comments were made at a future deterrent industry day event in June last year.

When the "speaking notes" of the event were initially released, officials blanked out the final sentence referring to the warheads, the Guardian says, but the decision was overturned on appeal and the pivotal sentence was reinstated.

An MoD spokesman said: "As stated in the December 2006 White Paper Future of the UK's Nuclear Deterrent, decisions on whether and how to refurbish or replace our existing nuclear warheads are likely to be necessary in the next Parliament.

"To inform those decisions, we are undertaking a detailed review of the optimum life of the existing warhead stockpile and analysing the range of replacement options that might be available.

"Decisions on a successor to the life extended D5 missile are not expected for some time."