If London's famous Big Ben wants to keep ticking like clockwork, it will have to undergo "urgent"—and expensive—repairs, a new report reveals.
To keep Parliament's iconic Elizabeth tower—Big Ben is actually the name of the bell that rings the hours—in operation, taxpayers may have to fork out up to £40 million ($61.9 million) to repair the clock's hands, pendulum, mechanism and tower, according to a report seen by Sunday Times and The Mail on Sunday.
In the report presented to the cross-party Commons Finance Committee, the authors suggested a complete refurbishment would cost an estimated £29.2 million, however, if the problems aren't fixed altogether, the cost could amount to £40 million.
Officials acknowledged that it could cost as little as £4.9 million "to prevent the clock from failing", but encouraged that if the issues are tackled now, the likelihood of it costing as much as £40 million would be reduced. A full £29m fix would see the clock stopped for four months, but could be longer if the situation is not sorted soon.
"There are major concerns that if this is not carried out within the next two to three years, the clock mechanism is at risk of failure with the huge risk of international reputational damage for Parliament."
"In the event of a clock-hand failure, it could take up to a year to repair due to the scaffolding needed," the report said.
With Big Ben making its first chime in 1859, this isn't the first time concerns have been raised over the building's wellbeing. In 1976, the Great Clock suffered a mechanical failure which led to repairs taking place across nine months.
As recent as August 2015, Big Ben was branded as "temperamental" after its chimes became out-of-sync by up to six seconds, and in 2007 the bells were silenced for seven weeks, to undergo key maintenance.
British taxpayers are already facing a multibillion-pound bill for restoring the Palace of Westminster, depending on when and how long the refurbishment takes.
Parliament released a statement revealing that a "feasibility study and survey work" had been carried out on Elizabeth Tower and the survey identified damage to the tower, including "cracks in (the) masonry, water ingress and erosion." The study is currently under review.
"Committees of both Houses are currently considering the study and will provide advice to inform the business case for how best to proceed," a parliamentary spokesperson said in a statement.
"No decisions on works, timescales or costs have been agreed."
—By CNBC's Alexandra Gibbs, follow her on Twitter