MPs and peers could leave the Palace of Westminster for up to two decades, under restoration plans that could increase the cost of repairs to £14bn, according to The Sunday Times.
This would treble the initial budget expectations to renovate the palace which is set to begin in 2027 and includes both House of Commons and House of Lords.
The plan, considered the ‘worst-case scenario’, will be one of several options presented by The Restoration and Renewal Sponsor Body.
The authority was set up in 2019 to oversee the project with a board including MPs, peers, historians and infrastructure experts.
It will also reportedly present less drastic options such as a 12–15-year exodus from the building.
Around 90 per cent of the costs will be spent saving the building and replacing the outdated and obsolete services, such as the electrics, gas, water, heating and sewerage, which dates from the 1880s.
Improvements are also required to make the building more accessible for people in wheelchairs, who cannot get to many of its thousand-plus rooms on four floors with 65 different levels without assistance.
In 2018, MPs backed a “full decant” proposal, which would involve moving into Richmond House in Whitehall for about six years.
However, the expectations at the time of the vote were that the refurbishment would cost about £4 billion, with later estimates suggesting the figure could reach about £7 billion.
It is also understood by the newspaper that the range of “decant” options presented to MPs will all take longer than the original six-year timeframe.
The last time MPs left was during the Blitz in 1941.
Prior to the vote three years ago, some MPs pushed for the rebuilding work to go-ahead while business continued on the site.
This is unlikely to be a viable option, as the restoration body has carried out the first detailed survey of the required building work, and concluded that doing the work with MPs and peers in the building would mean it would take more than 30 years.
The cost of managing the deterioration of the building is rising, and recent maintenance and continuing projects cost £127m in one year alone.
Weekly costs more than doubled between 2015 and 2019 to about £2.5m.
There are now growing fears the 19th-century building is falling down faster than it can be repaired.
Ten years ago, a parliamentary report said that the Palace of Westminster had so many fire risks, leaking roofs and asbestos hazards that if it “were not a listed building of the highest heritage value, its owners would probably be advised to demolish and rebuild”.