Several Labour MPs have vowed to break ranks and defy Jeremy Corbyn ahead of a key vote in the Commons on the Government’s landmark EU Withdrawal Bill.

Former minister Caroline Flint, who represents the Don Valley constituency that voted to leave the European Union, said she would defy the party’s strict three-line whip and accused opponents of the Bill of wanting to “thwart the result of the referendum and prevent or delay the UK leaving the EU”.

The EU Withdrawal Bill – often referred to as the Repeal Bill – will overturn the 1972 act that took Britain into the European Economic Community.

Its aim is transpose relevant EU law onto the UK statue book when the UK formally leaves the bloc in March 2019 in order to avoid a legal vacuum after Brexit. Votes on the Bill are expected after midnight.

Last week Mr Corbyn’s office said that the Bill was “completely unacceptable,” as it hands authority to ministers to amend the law without normal parliamentary scrutiny, under so-called Henry VIII powers.

But despite the command from the Labour leadership - instructing MPs to vote against the Bill at its second reading – and opposition from the Liberal Democrats and the SNP, it is expected the Government will win the vote, passing the first parliamentary hurdle.

Joining Ms Flint in supporting the Bill, former Labour welfare minister Frank Field told MPs on Monday that he would rather prefer to see the draft legislation simplified to include the “crucial” details.

Another Labour MP, Kevin Barron, said he would abstain on the Bill as a “vote against would be a contradiction of the promises I was elected on, only a few months ago”. The prominent Brexiteer Labour MP Kate Hoey is also expected to back the Government.

Despite concerns raised by several prominent Conservative backbenchers it is unlikely that any will defy the Government’s Bill – even after it was described by one last week as an “astonishing monstrosity” piece of legislation.

Bob Neill, the former Conservative minister, added that he would support the Bill but warned it was “necessary” but that there were a “number of areas” where it needed “improvement” in the committee stage.

Maria Miller, the Tory chairwoman of the Women and Equalities Select Committee in Westminster, echoed her colleague’s view, adding that one amendment to the Bill was needed explicity committing to “maintaining the current levels of equality protection.”

Three votes are expected, on a Labour amendment, the main second reading motion and the programme motion, which sets out the time available for MPs to go through the Bill line by line in the Commons.

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There are currently a guaranteed 64 hours over eight days for the committee stage, when amendments can be made, but concerns have been expressed by Tory and Labour MPs that this will not be enough time given the constitutional significance of the legislation.

If the Government motion setting out the time for debate is defeated, ministers will have to consider an alternative timetable.

In the Commons, Brexiteer Peter Bone, a prominent Conservative MP, said Commons leader Andrea Leadsom should extend the committee stage for the Bill. “I notice this particular programme motion is one of the better ones because it's eight days long and has eight hours protected time,” he said.

“I'm fed-up of sitting here waiting for a debate to come on, only to find there were statement after statement to reduce the time we have to debate it.