LONDON, England (AP) — This is not a metaphor: Britain’s Parliament is a mess.

The 19th-century building is crumbling, leaky, infested with vermin, and riddled with asbestos.

After years of dithering, lawmakers yesterday moved out of the building to allow several years of major repairs. The plan will cost billions, but experts say the alternative could be catastrophic.

“This debate arguably should have taken place about 40 years ago,” House of Commons leader Andrea Leadsom told lawmakers, adding that the building “is in dire need of repair”.

Legislators voted to back a call for lawmakers and staff to leave the building by the mid-2020s — a plan known as a “full decant” of Parliament. It’s estimated the repairs will take six years and cost about 3.5 billion pounds ($5 billion).

The decision came after warnings about the risks of delaying.

“It might be an exaggeration to say that Parliament is a death trap,” Conservative lawmaker Damian Green said. “But it’s not a wild exaggeration.”

Experts have issued increasingly urgent warnings about the state of the neo-Gothic Parliament building, one of London’s most famous landmarks and a UNESCO World Heritage Site. Reports have sounded alarm bells about leaky roofs, temperamental steam heating, antiquated plumbing, crumbling stonework, and ventilation shafts clogged with old pipes, wires and asbestos.

Yesterday’s vote backed a 2016 report commissioned by parliamentary authorities which said the building is at risk of a flood or fire that could leave it uninhabitable. The issue still has to be considered by the House of Lords, Parliament’s upper chamber.

Caroline Shenton, former director of the parliamentary archives and author of The Day Parliament Burned Down, said that without major repair work, Britain could lose “the most iconic, famous building in the country.”

“It could just simply be a utilities failure that brings the whole thing to a halt — the electricity goes, the water stops working, the loos stop flushing,” she said. “But something more catastrophic could happen.”

David Leakey, who retired last year as Parliament’s head of security, has said that without major work Parliament could be “another Grenfell Tower” — the London high-rise that burned down last year, killing 70 people.

Despite the warnings, lawmakers had put off making a decision for several years. Some worried the public will resent the expense. Traditionalists are reluctant to leave the historic Commons and Lords chambers, the subsidised bars and restaurants and the riverside terrace with its magnificent view across the Thames.

Some modernisers think a permanent move to a new building — perhaps even one outside London — would make politicians less out of touch with the people they serve.

Scottish National Party lawmaker Pete Wishart urged his colleagues to “make this beautiful building a tourist attraction … and let’s design and create a Parliament for the 21st century”.

Shenton said she hoped today’s lawmakers would remember history. The current Parliament building, designed by architect Charles Barry, was built after fire destroyed its predecessor in 1834.

Shenton said authorities had debated what to do about their aging building for years before the 1834 blaze.

“Nobody could make a decision,” she said. “In the end, the decision was made for them.”