Parliamentary officials have defended ordering Big Ben's bongs to be silenced for four years while renovations are carried out, insisting workers' hearing would be put at "serious risk".
Brexit Secretary David Davis said stopping the chimes was "mad" as he dismissed health and safety concerns linked to the clock tower's restoration and urged the estate's authorities to "just get on with it".
The move was also labelled "entirely bonkers" by Conservative MP James Gray who sat on the administration committee which first approved the work.
But officials said the deafening chimes are being stopped to protect workers who are renovating the Elizabeth Tower that houses the Great Clock and its bell.
Following the backlash, they put out a fresh statement insisting workers on the 100 metre high scaffolding around the tower could also be startled by the 118 decibel bongs.
And they 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 statement said: "It would not be practical or a good use of public money to start and stop the bells each day. In addition, as we cannot fully predict the times that staff will be working on this project, it would be impossible to reconnect the bells on a regular basis."
Work on restoring the Great Clock, which means the bongs would be automatically silenced, will take around two years.
The statement added: "Constant proximity and prolonged exposure to the chimes would pose a serious risk to the hearing of those working on the scaffolding or in the Tower.
"Whilst hearing protection provides a suitable short term solution to the 118 decibel chiming and striking of the bells, it is not acceptable for those working for long periods in the vicinity of Big Ben. In addition, it is vital for workers to be able to communicate with one another on site, or to raise an alarm should the necessity arise.
"This would not be possible were the bells to continue to sound throughout the works. Workers on the scaffolding could also be startled by the loud sudden noise, with consequences for their own safety and those of other people in and around the tower. The only way to ensure people's safety is to temporarily stop the bell."
It will be the longest period Big Ben has been silenced in its 157-year history and will begin after noon on Monday August 21.
The bell will still ring out for important national events such as New Year's Eve and Remembrance Sunday.
The £29 million renovation includes the installation of a lift and repairs to the clock's hands, mechanism and pendulum.
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.
Mr Davis told LBC radio: "I think it's mad, I'd forgotten of course, I've been out of government for a lot of years, and I've forgotten how long it takes to get the approvals for this and the approvals for that.
"There's a sort of rude phrase which I will shorten to 'just get on with it'.
"When I was in business, it was my standard line, just get on, just do it, don't faff."
He added: "I actually can't understand, I haven't been in the details... I can't understand why.
"There's hardly a health and safety argument, it's replacing a bell.
"I mean maybe it's to do with all the trouble about the £3 billion they want to spend on Parliament, who knows? Also an interesting problem.
"They should get on with it."