The Government’s key piece of Brexit legislation has been delayed due to a major push from MPs to force changes to it.

The EU withdrawal Bill will now not be debated next week after some 300 amendments were demanded by MPs, with many of them thought to enjoy enough support among Conservative MPs.

If Theresa May were to suffer a defeat at the hands of Labour and Tory rebels on her critical piece of Brexit legislation it would once again call into question the credibility of her administration.

Theresa May caught in Brexit trap after EU leaders block future trade talks

It came after the EU’s chief negotiator Michel Barnier warned of a “disturbing” deadlock in Brexit negotiations, with Ms May facing pressure to make further concessions to move talks on to future trade.

Leader of the House Andrea Leadsom confirmed that the Government was not yet ready to take its Brexit Bill before the House of Commons.

She said that as well as the 300 amendments, some 54 new clauses have also been proposed by MPs who have concerns.

Around 13 are thought to have enough support from Tories to see the Government defeated in a Commons vote, with ex-attorney general Dominic Grieve leading a drive to tighten up the legislation’s language.

Ms Leadsom told MPs: “Those proposals are being closely evaluated.

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“That is taking a bit of time so that we give proper, thoughtful, well considered responses to them. We will, of course, be bringing forward the Committee of the whole House just as soon as we are able to do so.”

Labour seized on the delay calling for Ms May to change the Bill, claiming it was not going before the Commons next week because the Government was afraid pro-Europe Tory rebels would back amendments to it.

Shadow Brexit Secretary Sir Keir Starmer told the BBC: “The Tories' Repeal Bill is simply not fit for purpose.

“It would give huge and unaccountable power to ministers and puts vital rights and protections at risk.

“Theresa May must start listening to the legitimate concerns of Labour and some of her own MPs by urgently changing approach.”

Ms May is caught in a Brexit trap after EU leaders ruled Britain must pay up to secure future trade talks, while her own MPs demanded she make no more concessions.

Barnier: The Brexit agreement will not be based on concessions

The heads of the EU states agreed the UK had not made “sufficient progress” on the withdrawal divorce terms, according to a leaked statement drafted by Donald Tusk, the President of the European Council, just hours after confirmation that the talks are deadlocked.