Aircraft carriers bill 'likely to top £6 billion'

When they were signed off by Labour - the project cost was £3.5 billion.

Today, Ministry of Defence sources acknowledge they are about to announce the cost will now top £6 billion.

And the first of the two 65,000-tonne aircraft carriers still won't be in service until the end of the decade.

It will make for an interesting session of Defence Questions in the House of Commons this afternoon.

Labour's recently appointed Shadow Defence Secretary has already been on the attack.

Vernon Coaker saying: "“Britain deserves better than this shambolic approach to our nation's defence.”

But you can bet the Defence Secretary Philip Hammond will say the cost overruns are a consequence of the terms of the original contract - signed by the last Labour government.

The latest projection of the bill for the new ships is £6.2 billion - that is £800 million more than the most recent estimate.

Part of the additional cost has come from the decision to change the type of jet which will fly from the aircraft carriers.

The Ministry of Defence reversed an earlier U-turn (yes that is a U-turn on a U-turn) on the F-35 aircraft.

Labour had ordered STOVL - Short Take Off and Vertical Landing - jets.

The first Conservative Defence Secretary, Liam Fox, scrapped that decision and ordered Carrier-type F-35s - which required catapults and traps to be fitted to the ships.

The current Defence Secretary then re-ordered the STOVL planes.

That - farcical - process added £200 million to the costs - double the initial estimates.

HMS Queen Elizabeth will not start trials until 2016 at the earliest and will not be fully operational until 2020.

HMS Prince of Wales will be completed next.