Lib Dem shadow minister for business Lorely Burt has written to the business minister John Hutton asking why the enquiry is taking so long. Burt hopes to bring the matter up with the minister today in the Commons.

Accountancy Age revealed earlier this month that nearly three years on, the Rover investigation has cost taxpayers more than £11m. This includes £95,094 on hotel costs, with a further £29,279 on subsistence, and expenses of the investigators of the BDO Stoy Hayward team, whom the Department of Trade & Industry appointed to lead the inquiry.

A spokesman for Burt said she intended to remind Hutton of a minister’s fiduciary duty to get good value for public money.

Commons select committee for business chairman Peter Luff has pledged to ask questions around Rover and said his committee would launch an ‘investigation into the investigation’ if DBERR failed to provide satisfactory answers.

The move raises the prospect that BDO investigators, including Gervase MacGregor, could be called to answer questions about their spending at a select committee grilling at Westminster.

Committee member and Labour MP Lindsay Hoyle said an inquiry could be requested once the investigation is complete.

‘We have to have them in to explain why it has been taking so long. The committee has shown a keen interest in the car industry and the people investigating it should have some answers for us,’ Hoyle said.

Julie Kirkbride, a Tory committee member, said she would support an inquiry. ‘It is hard to justify why it should take so long and cost so much money. On the other hand, there is no control from the taxpayers over the level of fees racked up during the enquiry.

‘This is a good case for looking at the proportionality, reasonableness and accountability in the setting up of these enquiries,’ Kirkbride said.

DBERR declined to comment.