LONDON • British Prime Minister Theresa May was slated to begin a major parliamentary battle over Brexit yesterday, facing competing demands by MPs to change her strategy as tensions rise among her scandal-hit ministers.

MPs have their first chance to scrutinise the EU Withdrawal Bill, which would formally end Britain's membership of the European Union and transfer four decades of EU legislation into UK law.

The government faces potential defeat on key amendments to the Bill if rebel Conservative MPs ally with the main opposition Labour Party, increasing the risks for Mrs May's perilously weak minority government. The government said it would ensure legal certainty when Britain leaves the bloc in March 2019.

But critics warn the EU Withdrawal Bill, also known as the Repeal Bill, represents a power-grab by ministers, while others see the legislation as a chance to shape Mrs May's Brexit policy.

Lawmakers, including members of Mrs May's own Conservative Party, have tabled 188 pages of amendments to the Bill, which will be debated in groups over eight days spread over the coming weeks.

The showdown comes as the Prime Minister, weakened by a June election in which she lost her parliamentary majority, struggles to assert her authority even over her own Cabinet.

Two ministers have quit in the past fortnight while two others stand accused of instructing Mrs May how to run Brexit.

The Premier is also under increasing pressure from Brussels to come up with a financial offer to keep negotiations on track, with a crunch summit of EU leaders looming in mid-December.

The pound dropped on Monday amid reports that dozens of Conservative MPs were backing a move to oust Mrs May.

The toughest votes are expected in the coming weeks, as Conservative MPs seek to reduce the powers the Bill gives to ministers to change EU laws as they are transferred across.

On the eve of the debate, the government made an apparent concession to rebels by promising a separate piece of legislation that would allow Parliament to have a binding vote on any Brexit agreement.

Labour's chief Brexit spokesman Keir Starmer said the proposal was "a significant climbdown from a weak government on the verge of defeat".

However, Brexit Secretary David Davis conceded that even if MPs failed to back that legislation - the Withdrawal Agreement and Implementation Bill - Britain would still leave the EU on March 29, 2019.

AGENCE FRANCE-PRESSE