The cost of the new Scottish parliament building is to exceed £400 million, it has been announced.

Opposition parties rounded on the government after the latest increase in the projected cost of the building which will house Scotland's 129 MSPs.

As the public inquiry into the project gets underway, pressure is building on politicians at Westminster.

Whilst the new parliament is now the responsibility of MSPs, the initial decisions on location and design were taken by the UK government.

The Scottish Nationalist Party said ministers in London must be held accountable for the massive cost over-run.

Scotland's shadow finance minister Fergus Ewing said the Scottish executive and the Labour government would have to take responsibility for the "fiasco".

"The reason that the costs are out of control is because the wrong type of contracts were drawn up for the building's construction in the first place," he said.

"The design has been worked out as they have gone along and the additional costs are a direct result of the decision made by Labour in London pre-devolution, which was then rubber stamped by the Lib/Lab executive in 1999.

"There is an extremely strong case for Westminster to fork out for all of the extra costs which resulted from their decision.

"If they refuse on the grounds that the Scottish parliament approved the project, they are wrong - it was the sole responsibility of the Lib/Lab MSPs who voted it through on party lines on the 17 June 1999."

And he predicted that costs could soar further still.

"This fiasco is a Labour one, supported by their backing group the Scottish branch of the Lib Dems," said Ewing.

"I suspect that there will be more rises to come and it's about time that the government both in Scotland and at Westminster took responsibility for this farce which is of their own making."