Ministers could be forced to seek a vote of approval from MPs to scrap swathes of European Union rules after the Lords inflicted a heavy defeat on the Government.
Peers voted today in favour of greater parliamentary scrutiny of the scaled-back list of EU laws to be ditched at the end of the year, with the potential for both Houses to debate and vote on changes deemed to have a significant impact on the UK statute book.
It means the Retained EU Law (REUL) Bill could be watered down even further if MPs back the amendment when the proposed legislation returns to the Commons.
But sources close to Kemi Badenoch, the Business and Trade Secretary, said she would not be deterred from her ambition to scrap as many EU laws as possible by the year-end.
"Kemi is keen to get as much unnecessary REUL off the statute books by the end of 2023 as possible," they said.
"Over 2,000 EU laws are already going and she's pushing Whitehall departments to do more, and she won't be deterred from that exercise."
The Government had rowed back on plans to ditch all remaining EU laws by the end of the year, sparking a furious backlash from Brexiteers.
Jacob Rees-Mogg, the former Brexit secretary, called the decision "pathetically under-ambitious" today.
The former cabinet minister, whose speech at the National Conservatism conference was interrupted early on by a protester warning about "fascism", said the Government's "U-turn" over scrapping EU laws was a "defeat of ambition, prosperity and democracy".
Critics have warned the REUL Bill allows for limited parliamentary scrutiny, with ministers able to make sweeping changes through secondary legislation.
The Lords amendment, backed by 245 votes to 154, a majority of 91, would require EU laws earmarked for the scrap heap to be sifted by a joint committee at Westminster.
Where the move was judged to represent a significant change to current UK law, it would have to be debated and voted on in both Houses.
Explaining the need for the amendment, Lord Hope of Craighead, a former deputy president of the UK Supreme Court, said: "There remains a very significant gap. There is no provision for parliamentary scrutiny in a proper sense of those words.
"It is the greatest of ironies that the taking back control of our laws, which is what Brexit is all about, has resulted in handing back this control to ministers and civil servants, and not to Parliament.
"Parliamentary scrutiny over what they are doing is not there, other than in the most superficial way."
He was supported by Brexit-backing Lord Hamilton of Epsom, a Tory former minister, who argued that Parliament should decide on retained EU laws rather than the civil service, which he likened to an "old banger in need of a serious MOT".
But Tory frontbencher Lord Callanan told peers the change was "unnecessary".
Peers also backed a move to give Parliament and the devolved administrations the final say over whether retained EU rights and obligations should be ditched, rather than ministers.
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