Big Ben bongs could cost taxpayer £40 million

The taxpayer faces a bill of up to £40 million to keep the famous "bongs" of Big Ben sounding, according to a report.

The clock is said to be so dilapidated that it could grind to a halt altogether unless drastic repairs are carried out, the report presented to the cross-party Commons Finance Committee says.

The report set out a £29.2 million plan for fixing the issues which would see the mechanism shut down for four months - believed to be the longest stoppage in its 156-year history.

The document, seen by the Mail on Sunday, said: "The clock currently has chronic problems with the bearings behind the hands and the pendulum.

"Either could become acute at any time, causing the clock to stop - or worse."

Action is also needed to combat "severe metal erosion, cracks in the roof and other structural defects" in the Elizabeth Tower.

It said that if the work is not completed in the next two to three years, the clock mechanism is at risk of failure with the "huge risk of international reputational damage for Parliament".

The proposed £29 million "full refurbishment" would involve the clock being stopped for four months.

The previous longest shutdown is thought to have been in 1976, when the clock stopped intermittently for 26 days over nine months while repairs were carried out.

Officials admit it would cost only £4.9 million "to prevent the clock from failing", but they suggested the cost could rise to a cumulative total of £40 million if the underlying problems are not dealt with in one go.

The public purse is already facing a massive restoration bill of up to £7 billion for the crumbling Palace of Westminster.