A controversial new office block for MPs, already under fire for exceeding its pounds 150m budget, is to be lined with English oak - one of the most expensive woods on the market.
Portcullis House, whose cost has swelled by more than pounds 100m, to pounds 250m, since it was first conceived, is to have a lavish oak panelled interior in the style of the Palace of Westminster.
The 200 MPs' offices will have oak-panelled walls and desks for members and their secretaries.
Although the exact cost is secret, it is estimated that the bill for the panelling alone will exceed pounds 100,000.
The plans have been condemned as "out of control" by senior Conservatives, who are to call for an inquiry into the extra costs by the committee overseeing the building.
"MPs will be writing to the House of Commons Accommodation and Works Committee to try to establish exactly what's going on with this spending," a Conservative Party spokesman said. "English oak panelling is exorbitant. It's spiralling out of control."
The interior of the building is to be shown publicly for the first time in the coming weeks.
Sir Michael Hopkins, the architect responsible for the new-look Lord's cricket ground grandstand and the Glyndebourne Opera House, has designed a prototype "show room" replete with carpets and furnishings near the Millennium Dome. The interior of the building will be minimalist and simple. But master craftsman say a similar effect, using other woods, can be obtained at a proportion of the cost.
Planks of English oak cost about pounds 90 for 100ft and the cost of turning it into panels will escalate the bill considerably.
"English oak is not used much these days because it's so expensive," a craftsman at Framework Joinery, Stevenage, said. "It's similar to European oak but it's wilder. It's one of the most luxurious woods and you have to have someone who knows how to fit it."
MPs who have seen the mock-up compare it to the style of the European Parliament, with modern desks and lots of space.
The carpets will be green, similar to those in the House of Commons, but without the parliamentary portcullis emblem.
And to avoid further controversy about wallpaper, the walls are to be blank, with a concrete-style wash. Blinds will replace the heavy Pugin- style curtains of the House of Commons.
MPs allocated rooms in the new offices will have a choice of furniture, including black leather chairs, coffee and meeting tables.
Portcullis House, opposite Big Ben, has already come under fire after it was revealed that the giant pre-cast concrete panels did not fit because the "wrong type of concrete" had been used.
"English oak will cost you an arm and a leg,' said a spokesman from AW Champion, timber merchants. "Its one of the more expensive hardwoods there is. There are far cheaper options and other oaks you can use."
The new office block, above Westminster Underground station, will have shops, conference and meeting rooms, public facilities as well as offices for MPs and support staff.
Designed in the shape of a rectangle, it will enclose a huge glass-roofed courtyard atrium complete with trees and ponds.
Some MPs believe the initial cost is justified as a long-term investment and that the building should have special features unlike ordinary office blocks.
"The building is supposed to last for 200 years. It is being built to last and is not exorbitant or expensive," said an MP on the Commons committee overseeing the work. "It is a parliamentary building so it needs to have some unique features."