Dr Ware said: “The more things become antiquated the changes of a bigger
crisis grow. It has already burned down once.”

Part of the problem is that the building is made from Anston limestone, which
is subject to erosion.

A series of photographs published on the website of Business
Insider laid bare the damage to the building’s fabric including the
rusting cast-iron roof.

Dr Ware said: “There is very little down time and the problem is how on earth
you undertake fundamental renovations on the scale required under those
circumstances.”

A report on the future of the Palace of Westminster concluded in 2012: “If the
Palace were not a listed building of the highest heritage value, its owner
would probably be advised to demolish and rebuild.”

Mel Barlex, the programme’s parliamentary and technical director of estates,
added: “When things go wrong you can’t shut the Palace down so you end
putting new cables and pipework in without removing the old ones.

“So you eventually shrink the amount of available of space you have and make
it more difficult to access the areas that you need to get to.”

One of the major problems is that asbestos – a deadly substance which was used
in the 1940s and 1950s to fireproof buildings – had been “liberally applied
all around the building – not just as insulation but in light switches,
toilet systems and as a sound suppressant”, Mr Barlex said.

Mr Barlex added that the need to shut down parts of the Palace of Westminster
meant that on one occasion an MP missed a narrow vote in the House of
Commons.

He said: “Within six months of my joining I had a member stuck in a lift as a
vote was underway. The legislation was ultimately passed by seven votes.
That brought home just how serious these issues are.

“The worst problem we’ve had was a flood in 2010. A policeman walking along
one of the corridors noticed some water coming in through the ceiling. A
pipe had split pouring 30,000 litres of water in 15 minutes, and it took us
three weeks to fully recover.”

MPs and peers will be asked to decide in 2016 to move out fully or partially
make way to allow builders to start a major refurbishment of the Palace of
Westminster.