MPs urge caution over Westminster repairs
More scrutiny is needed of plans to spend billions of pounds renovating the Houses of Parliament, MPs say.
The Commons Treasury Committee said no final decision should be taken on how to proceed until it had investigated the options.
"Large construction projects often go wrong," the committee said, and MPs would "bear the brunt" of criticism.
Proposals have been put forward to move MPs and peers out of the building while urgent repairs take place.
The recommendation, which has been costed at £4bn, was made in September by the Joint Committee on the Palace of Westminster.
It would involve MPs moving into the Richmond House building on Whitehall currently occupied by the Department of Health.
The Treasury committee said it would also examine an alternative option, opposed by the joint committee, of a "partial decant" where the Commons and Lords took turns to move out while repairs were taking place.
It also said it would scrutinise the assessment by consultant Deloitte that this option would cost more and take longer.
The Palace of Westminster, a World Heritage Site, has asbestos, leaks, old electrics and is said to be at high risk of "catastrophic failure".
In a preliminary report, the committee said: "Restoration and renewal of the Palace of Westminster is a major undertaking which will last many years and cost billions of pounds."
The project will have a major impact on public perception of the work of the Commons and Lords, it said.
The committee added: "Given the enormous sums involved, it would be vital even in normal times that the case for the spending and its cost-effectiveness were thoroughly scrutinised and that the plans were rigorously challenged.
"It is even more important at a time of austerity, when restoration of the Palace will be competing for funds with many hard-pressed parts of the public sector."
The committee concluded that until its report had been published, it would be "imprudent" for MPs to make a final decision.
Last week Parliament's spending watchdog, the Commons Public Accounts Committee, said vacating the Palace of Westminster was the most economic and efficient option, and that further delays would add millions to the cost.