The “bonfire” of EU legislation by the government is to scrap less than a quarter of the estimated European laws on statute books, MPs have been told.

Sky News understands Eurosceptic Tory MPs were told by Business and Trade Secretary Kemi Badenoch just 800 of roughly 4,000 laws are expected to be ditched by the end of this year.

Brexiteer Conservatives – including the European Research Group – will be angered by what they will see as a watering down of a promised “bonfire” of EU “red tape”.

Rishi Sunak said at his agenda-setting New Year’s speech that a “big part” of increasing growth in the country was “seizing the opportunities of Brexit”, which includes making sure that “regulations are agile” and support “innovation”.

“We have new opportunities and freedoms to do that, and we are absolutely going to seize them to deliver for the country,” he added at the time.

Jacob Rees-Mogg was the Brexit opportunities minister who was shepherding the Retained EU Law Bill through parliament before he left government when Mr Sunak took office.

This law would revoke EU laws by the end of this year which are judged not to be essential.

Mr Rees-Mogg branded the update from Downing Street as “thin gruel”.

And one Eurosceptic MP told Sky News: “I’m extremely disappointed.

“It goes against all the assurances we have had from the prime minister.

“In fact, I’d be very surprised if he supported it.”

But a person previously involved in Brexit discussions welcomed the move – and highlighted its pragmatic nature.

Raoul Ruparel, who advised Theresa May on Brexit, said that this was “surely how the process was meant to work” – and that removing laws “for the sake of it” would be “nonsense”.

He also pointed out that the ERG’s failure to muster a large rebellion over the government’s new agreement with the EU on Northern Ireland may have emboldened Downing Street.

Naomi Smith, the chief executive of the anti-Brexit campaign group Best for Britain, said: “Unless it is scrapped entirely, this bill will automatically remove workers’ rights, food standards and environmental protections by the end of the year while unleashing economic chaos in the UK.”

Sources close to Ms Badenoch did not deny she made the remarks.

A government spokesman said ministers continue to support the bill and removing “unnecessary” EU laws – but did not commit to completing the removal by the start of 2024.

He said: “We remain committed to ensuring the Retained EU Law Bill receives royal assent and that the supremacy of EU law ends with unnecessary and burdensome EU laws removed by the end of this year.

“Once passed, the bill will enable the country to further seize the opportunities of Brexit by ensuring regulations fit the needs of the UK, helping to grow our economy and drive innovation.”