Renovations that will silence the Big Ben bell in the British parliament's famous clock tower for four years will cost more than double the original estimate, officials said today.

The commissions overseeing the work at Westminster have agreed to set aside 61 million pounds  (€63 million) as opposed to the 29 million pounds estimated last year.

The House of Commons said there was now a greater understanding of the work that needed to be done on the masonry of the Elizabeth Tower, which houses the famous bell, and that surrounding ground conditions were more complex than initially thought.

"We acknowledge that there have been estimating failures and we understand the concern of the commissions," the Clerk of the House of Commons, the Clerk of the Parliaments and the Director General said in a joint statement.

Big Ben ceased its regular bongs in August, and will remain silent for most of the next four years while the works are carried out.

The hammers, which have struck the 13.7 tonne bell every hour for most of the last 157 years, will be locked and disconnected from the clock, although the bongs will still sound for important events such as the New Year's Eve celebrations.