London (AFP) – British Prime Minister Theresa May will on Thursday begin trying to sell her Brexit deal to parliament, boosted by the backing of her cabinet but facing a mutiny in her own party.

She will set out the terms of the draft withdrawal agreement with the European Union to the House of Commons, which must approve the deal before Brexit on March 29.

European Council President Donald Tusk will meanwhile give his verdict in Brussels, with London hoping he will call a leaders’ summit later this month to seal the deal.

May won her cabinet’s approval for the agreement during a five-hour meeting on Wednesday, an important step that helped allay growing fears of a disorderly divorce.

“It moves the UK one step away from the nightmare precipice of no deal,” said the CBI lobby group.

But while EU negotiator Michel Barnier applauded the “decisive progress” made after months of deadlock, he warned there was “lots of work” still to do.

The volatility of the pound on Wednesday — plunging on unfounded reports of resignations before rebounding — highlighted how much uncertainty there remains around Brexit.

In particular, the outraged response by many MPs to the deal has heightened concerns that even when finalised, it will not pass parliament.

– Worst deal in history –

Hardline Brexit supporters in May’s Conservative party have cried betrayal over the agreement’s vision of a close future relationship between Britain and the EU.

Veteran MP Peter Bone warned May on Wednesday that she risked losing the support of “many Conservative MPs and millions of voters”.

Jacob Rees-Mogg, leader of an influential group of MPs, urged colleagues to reject the deal.

Former UK Independence Party (UKIP) leader Nigel Farage, a key figure in the 2016 Brexit vote, said it was “the worst deal in history”.

May insisted it “brings back control of our money, laws and borders, ends free movement (of people), protects jobs, security and our union”.

But she conceded there were “difficult days ahead” as she seeks to woo MPs.

EU leaders are mulling a special summit to seal the agreement on November 25, setting the stage for a Commons vote in early December.

The deal covers citizens’ rights, Britain’s financial settlement and plans for a post-Brexit transition period during which both sides hope to agree a new trade deal.

The most controversial element is a “backstop” plan to keep Britain in a customs union with the EU until a trade deal is agreed that avoids the need for border checks with Ireland.

Many Brexiteers fear this would leave Britain a “vassal state”, tied to the bloc indefinitely.

The same arrangement would see even closer alignment for the British province of Northern Ireland, something May’s allies, the Democratic Unionist Party (DUP), are resisting.

DUP leader Arlene Foster said she had a “frank meeting” with the prime minister on Wednesday evening, tweeting: “She is fully aware of our positions and concerns.”

– ‘No Brexit?’ –

Together the Conservatives and the DUP have a slender majority in the 650-seat House of Commons, but the scale of the rebellions have left May courting opposition MPs.

The prime minister also met Wednesday with Labour leader Jeremy Corbyn, who has indicated he will reject the Brexit deal.

But individual Labour MPs fear it is preferable to no deal at all.

In a statement outside Downing Street late Wednesday, May said her deal was “the best that could be negotiated”.

She said if MPs rejected it they faced Britain leaving without agreement, which experts says could lead to potentially catastrophic economic and legal disruption.

She also raised the risk of “no Brexit at all”, a warning likely intended for her eurosceptic MPs but which was seized upon with enthusiasm by campaigners for a second referendum.

“Yes! The alternative is putting this fiasco back in the hands of the people,” the pro-European Green party tweeted.

A small but growing number of Conservative MPs back a second vote with the option to stay in the EU, although May has rejected the idea.