Lord Fraser has accused civil servants of concealing the true costs of the new Scottish parliament building.

Turning to one of the last witnesses to the inquiry, chief architectural adviser Dr John Gibbons, he said: "It doesn't look very good, does it?"

Speaking during one of the last evidence sessions for his inquiry into management of the project, the peer suggested that a higher cost estimate of £89 million, prepared privately by cost consultant Hugh Fischer, was concealed when control transferred to MSPs in 1999.

Instead, civil servants adhered to a lower cost estimate of £62 million believing they could manage out the extra costs.

The lower figure was quoted in the parliament by the late Scottish secretary Donald Dewar.

"It looks rather as though those who were involved in this were determined to keep the figure down as low as possible even to the point of concealing it from the parliament in the hope that the project would go ahead," said Lord Fraser.

"It was a very narrow vote on this in the Scottish parliament in the middle of 1999. 

"Would it not have been appropriate to put the secretary of state in the position that he could tell parliament that the figure he had in front of him of what it was going to cost was £89 million?"

Dewar had acted "in good faith", he said.

"I have to tell you, Dr Gibbons, that I have done this job in the past and if people or civil servants generally take out professionally assessed figures, that would at least have been signalled," said the peer.

"I have read the reports to the secretary of state and there is no mention whatsoever that Mr Fischer thinks this is going to amount to a construction cost of £89 million.

"He makes an evaluation of the figure and this wasn't reported to the secretary of state and never allowed to go before parliament.  It doesn't look very good, does it?"

Counsel for the Scottish executive, Laura Dunlop QC, offered written submissions to address Lord Fraser's concerns, but he replied: "I don't want submissions, I want evidence."