Why Big Ben won't be chiming for the next four years

Crowds have gathered outside Westminster as Big Ben has fallen silent. Renovation work gets underway following a backlash from Theresa May and MPs over the proposed four-year timetable for the work.

Last week, Parliament said it would review the plans to silence the chimes for four years after the Prime Minister joined an MPs' outcry against the move.

People have gathered outside the clock tower to hear the chimes for the final time until 2021, except for special occasions.

But Liberal Democrat MP Tom Brake has said Big Ben could be allowed to chime on more special occasions.

It comes after a trio of Eurosceptic Tory MPs called for Big Ben to bong Britain out of the European Union on Brexit day, expected on March 29 2019.

Parliamentary officials have insisted workers' hearing would be put at "serious risk'' if the bell continued chiming.

Plans were already in place for the bell to chime on New Year's Eve and Remembrance Day.

Mr Brake said: "The House of Commons Commission has agreed to look at the issue when we're back, and what I take that to mean is look at whether there is perhaps more scope for the bells to be rung on other ad hoc occasions.''

He signalled it could be difficult to get Big Ben bonging sooner than 2021 as the clock that drives the bell is being dismantled, overhauled and tested, which will take at least two years.

"That is a major obstacle in the way of striking it much more frequently and for a long period of time,'' he said.

The 13.7-tonne Great Bell was last stopped for maintenance in 2007 and before that was halted for two years in 1983 for refurbishment, but has been stopped on a number of other occasions since it first sounded in 1859.

Parliamentary officials have insisted workers' hearing would be put at "serious risk'' if the bell continued chiming.

They warned that those using the 100-metre-high scaffolding around the tower could also be startled by the 118-decibel bongs.

They have dismissed suggestions the chimes could be restored during the hours that work is not being carried out, as the process takes about half a day to complete.

The renovation includes the installation of a lift and repairs to the clock's hands, mechanism and pendulum.

It was expected to cost £29 million but MPs have raised concerns that the bill could soar to £60 million.

A Commons' spokeswoman said: "As we are currently in a procurement process we are unable to comment on projected budget estimates at this stage.

"We expect to make an announcement regarding the contract in the autumn."