THE Ministry of Defence was accused of secrecy last night when it emerged the bill for a troubled Swan Hunter shipbuilding contract has gone up for a second time.

The cost of constructing two auxiliary landing ships has risen by a further £3m to £235m, to "ensure the vessels comply with the latest statutory safety requirements".

The latest increase, revealed in a parliamentary answer, comes on top of an £84m overspend which the MoD blamed on Swan Hunter's "underestimation of the engineering requirements".

The "revised contract" led the Conservatives to demand that Swan Hunter be denied lucrative work to build two giant aircraft carriers until it was properly explained.

And it resulted in a rare rebuke by the Commons Speaker, who criticised the MoD for "failing to give a full or up-to-date picture of the facts relating to the contract".

According to the latest parliamentary answer, the original design and build contract was valued at £148m - which means it has now gone up by 59 per cent.

Gerald Howarth, Tory defence spokesman, said: "This demonstrates the project has been very badly managed, something which the MoD has tried to keep secret from parliament.

"They must have known what the safety requirements would be when they drew up the contract, unless they have suddenly come in the last few weeks."

However, Defence Procurement Minister Lord Bach said: "The re-negotiation of the landing ship contract with Swan Hunter represents value for money for the British taxpayer."

Dari Taylor, Labour MP for Stockton South, has accused the Tories of a "smear campaign" to win extra work for the Portsmouth shipyard, in their Southern heartlands.

Swan Hunter, which has shipyards at Wallsend and at Middlesbrough, hopes to build one module of each of the two carriers, bringing in about £500m and creating 1,500 jobs.