As the investigation into the soaring costs of the new Scottish parliament building prepares to hear closing submissions, the SNP has urged first minister Jack McConnell to explain his role.

Lord Fraser's inquiry hears closing submissions on Tuesday and Wednesday from representatives of the executive and the Scottish Parliament Corporate Body.

But ahead of the hearings, shadow finance minister Fergus Ewing said the first minister should be called to give evidence.

The SNP argued that documents sent to McConnell detailing funding for the project "call into question" his involvement with the building project.

"These minutes are a myriad of new revelations and they reopen the whole question of Jack McConnell’s involvement in the Holyrood project," said Ewing.

"The SNP called for the executive to put a minister on the Progress Group from the start and they refused, saying that the parliament was responsible."

But he claimed that ministers were "secretly controlling the Holyrood Progress Group" through their officials who had asked "for a steer" on the issue.

"This suggests that the Scottish executive was running the show because what’s the point of asking unless you are speaking to the driver?" said Ewing.

"Jack McConnell's involvement in the Holyrood project must now come under serious scrutiny. He must give evidence to the Fraser inquiry."