The £500,000 cost of allowing Big Ben to bong on Brexit night is more than 30 times more than the bill for sounding Parliament's Great Bell on New Year's Eve, The Daily Telegraph can disclose.
The news risks undermining the House of Commons's Commission decision not to allow Big Ben to chime at 11pm on Jan 31 on grounds of cost.
It will put further pressure on Parliament to allow the bongs to sound. By lunchtime today £220,000 had been raised by members of the public to cover the cost of the Brexit night bongs.
The Commission formally rejected a request to allow the Great Bell to chime on Monday saying that contractors had said it would cost £500,000.
This covered the cost of reinstating a floor underneath Big Ben that was removed after New Year’s Day, as well as reinstalling the temporary equipment needed to make the bell sound
However that figure has been called into question after Sir Paul Beresford, a senior Tory MP, told MPs today that the bell cost just £14,200 to sound on other occasions.
Sir Paul told Tory MP Mark Francois in a Parliamentary answer: "The costs associated with striking Big Ben on Remembrance Sunday and New Year's Eve in 2019 were £14.2k including VAT on each occasion."
He added: The striking of Big Ben on these occasions was coordinated around the planned works so as to minimise the impact on the project costs and to ensure it did not result in any delay.
"If the project team are required to strike the bell with less notice, the costs would substantially increase due to the unexpected impact on the project schedule."
Mr Francois, the Tory MP who has been campaigning for Big Ben to sound, demanded to know why the cost was 35 times more on Brexit Night than on New Year's Eve.
He told The Daily Telegraph: "I have always suspected that these costs were inflated but I never dreamt it was 35 fold! What was becoming an embarrassment is now evolving into a scandal.
"I will be writing to the head of the National Audit Office [Parliament's spending watchdog] on Monday morning formally ask them to investigate the entire Elizabeth Tower project."
A spokesman for the House of Commons said: "The striking of Big Ben on these occasions was coordinated around the planned works so as to minimise the impact on the project costs and to ensure it did not result in any delay.
"If the project team are required to strike the bell with less notice, the costs would substantially increase due to the unexpected impact on the project schedule.
"The cost of striking the bell for New Year’s Eve and Remembrance Sunday has been factored in to the planned programme well in advance, to ensure that testing and striking have no impact on planned works, therefore causing no delay and minimum cost."
After Boris Johnson called on the public to “bung a bob” for Big Ben to sound the moment Britain leaves the EU, more than £130,000 was raised on the Go Fund Me crowdfunding site.
But the House of Commons Commission's ruling sparked an immediate blame game in Westminster, with Brexiteers pointing the finger at the Speaker and his Remain-heavy committee.
However, the committee, which includes six MPs, hit back, blaming the Prime Minister for encouraging the public to donate without checking whether it was even possible to sound Big Ben, which is currently undergoing a multi-million pound restoration.