House of Lords warns of a "breathtaking" power grab which will allow May's government "unlimited powers" to change UK law without scrutiny.

Tory MPs set to rebel over scope of the EU withdrawal bill, which will be debated for the first time today.

Lords committee warn that bill will fundamentally challenge "the constitutional balance of powers between Parliament and Government."

Corbyn set to oppose the bill despite rebellion from pro-leave Labour MPs.

LONDON – Theresa May's European UNion withdrawal bill will hand ministers wide-ranging powers that are "breath-taking in terms of both their scope and potency," the House of Lords has warned.

The bill, which will go before the Commons for the first time today, will allow the government "effectively unlimited powers" to changes large areas of UK aw without any effective scrutiny by Parliament, the Lords Constitutional Committee says in its interim report.

The report will raise fears among both Conservative and opposition MPs that the bill, designed to untangle British and EU law, will be abused as an unprecedented "power grab" by May's government.

Under the bill, due to be voted on next Monday, ministers will be able to use delegated powers and so-called Henry VIII clauses to make thousands of changes to Britain's legal and constitutional settlement without direct votes by MPs.

Opponents fear the government will use these powers to unpick decades of workers' rights, without parliamentary scrutiny.

The Lords report warns that "the Bill weaves a tapestry of delegated powers that are breathtaking in terms of both their scope and potency," adding that the bill will "fundamentally challenge the constitutional balance of powers between Parliament and Government."

It adds: "We are concerned about the delegated powers the Government is seeking in the European Union (Withdrawal) Bill. The number, range and overlapping nature of the broad delegated powers would create what is, in effect, an unprecedented and extraordinary portmanteau of effectively unlimited powers upon which the Government could draw," the report notes.

"They would fundamentally challenge the constitutional balance of powers between Parliament and Government and would represent a significant—and unacceptable—transfer of legal competence."

Tory and Labour MPs set to rebel over Repeal Bill

The bill is likely to pass its second reading on Monday, despite opposition from opposition parties.

However it could face heavy opposition in the committee stage later this year, when amendments to the wide-ranging powers contained within the bill are likely to be supported by a number of Conservative MPs. Tory backbencher and soft-Brexit campainger Anna Soubry is expected to lead opposition to the bill along with other senior figures including former Justice secretary Dominic Grieve.

However, Jeremy Corbyn, who has long been opposed to the bill, is also likely to suffer a significant rebellion on his own benches. A number of Labour MPs are concerned that the party's opposition to the bill will cost them votes among Leave-voting Labour supporters. Labour MP Graham Stringer told the Today programme that the decision to oppose the bill was a "mistake" and a "breach of trust".