LONDON, June 14 (Xinhua) -- British Prime Minister Theresa May was Thursday night facing the threat of a new revolt by her own Conservatives in the latest twist to the Brexit saga.

May went into what were among the toughest 48 hours of her premiership Tuesday when she faced the prospect of the House of Commons backing amendments to her crucial bill to pave the way for Britain to leave the European Union (EU).

In the event, May's government came through two days of intensive debates, overturning every major amendment that had been put forward by the unelected House of Lords.

In one crunch clash over the wording of what would be a meaningful vote on a final Brexit deal, May emerged victorious. But her win came after she made concessions to leading Conservative MPs.

The Guardian newspaper Thursday said May was walking a tightrope in being able to keep on her side her rebellious politicians, while at the same time ensuring leading Brexiteers did not themselves become rebels.

The fresh round of trouble emerged after Downing Street published on Thursday an amended version of the meaningful vote clause which will be presented next week to the House of Lords before returning for a final vote in the Commons several days later.

It emerged that her rebels, led by former attorney general Dominic Grieve, have rejected the new wording issued by May's office.

The Independent newspaper in London reported Thursday that some sources in Westminster were already speculating that it could cause a constitutional crisis, precipitating the collapse of May's administration.

The new government amendment to the Brexit bill set out what must happen if May announces before Jan. 21, 2019 that no deal has been reached with the EU either on the withdrawal agreement or the future relationship. If that happens, one of May's ministers must make a statement in Parliament within 14 days and give MPs an opportunity to vote.

Grieve had demanded an amendment, saying the government must seek the approval of parliament for its course of action, and that May and her ministers must be directed by MPs and the House of Lords.

Grieve told media in London the new version was unacceptable because wording made it impossible for MPs to change the government's proposals.

Keir Starmer, the main opposition Labour's chief Brexit spokesman said: "The government's amendment is simply not good enough. Theresa May has gone back on her word and offered an amendment that takes the meaning out of the meaningful vote. Parliament cannot, and should not, accept it."

The Guardian said it pointed to a new showdown with Conservative rebels, while the Independent added that May's compromise plan had fallen apart, plunging her into a fresh Brexit crisis.

Pro-Leave politicians have accused remain supporters of engaging in tactics to keep Britain in the EU, either by reversing the referendum decision or making it impossible for Britain to leave the bloc.

Under British law, government bills have to "ping pong" between both Houses of Parliament before a final vote takes place.

Meanwhile, Scottish National Party (SNP) politicians continued their attack Thursday on Westminster following the two-day Brexit bill debate which denied them the opportunity to discuss the impact of a Brexit deal on the devolved Scottish Parliament.

It has led to some politicians claiming the SNP is using the skirmish with Westminster to advance its cause for an independent Scotland. The Scotland's Daily Record newspaper in Glasgow reported Thursday that the Scottish and British governments were at war, with the two governments hardly talking to each other.

Nicola Sturgeon, leader of the SNP and Scotland's First Minister Thursday welcomed a statement by Murray Foote, former editor of the Daily Record, who announced he now supported an independent Scotland.

As editor of the newspaper, Foote ran a famous front page promise of more powers for Scotland if it voted "No" to independence. Now he says Brexit has changed his mind.

Sturgeon said on social media: "That Foote now supports independence is hugely significant. I'm delighted. Welcome aboard, Murray."