THERESA May’s precarious leadership is in the hands of her fractious MPs after she struggled through a brutal week over her European Union withdrawal plan.

The Prime Minister appeared to have gathered momentum on Friday after surviving a spate of resignations from her Government, but she is expected to face a series of challenges to her authority over the next few days.

Conservative MPs who have angrily denounced her draft agreement with European negotiators are expected to get close to the 48 signatures required to force a no- confidence vote in her.

A core of influential Cabinet Ministers who voted Leave in the 2016 referendum, led by Environment Secretary Michael Gove, will also meet within days in a bid to persuade May to change course.

The Tory civil war comes as senior figures in all the main parties at Westminster insist she will be unable to command a majority for her exit plan.

May last week unveiled the 585 page draft Brexit withdrawal agreement, which was put together following fractious discussions with the EU.

The UK is scheduled to leave the EU next year, but May’s problems arise from what happens after the completion of the transition period in December 2020.

Under the draft, if a long-term trade deal has been not agreed by the end of 2020, one option is for the transition period to be extended for a limited period.

An alternative, in order to avoid a hard border between Northern Ireland and the Republic of Ireland, is a “backstop” consisting of a single customs territory between the EU and the UK.

However, the backstop plan infuriated some of May’s backbenchers as they believe would prevent the UK from entering into new trade deals with other countries, which they argue is one of the main benefits of Brexit.

The UK would also be unable to cancel the backstop independently and would need the agreement of the EU, an outcome MPs fear would trap the UK.

Publication of the draft agreement led to the resignation of members of May’s Cabinet, including Brexit secretary Dominic Raab.

It also triggered a campaign on the backbenches to secure the 48 signatures required to force a no confidence vote in the leader.

However, the move to force a vote appeared to stall after MP Steve Baker, vice-chair of the pro-Brexit European Research Group, over-estimated the number of signatures.

Mr Baker had stated on a WhatsApp group that the number was “over 48”, which would have led to a contest, but he later backtracked and said his count had been “inaccurate”.

One senior Tory told the Herald on Sunday that the figure could reach 48 by Tuesday, which would lead to a vote soon after.

Another Conservative insider said a vote could be an “opportunity” for May if she won it convincingly.

“She would be able to say she has a mandate for the deal on the table,” he said.

Another threat for the Prime Minister will come when Gove, whose decision to stay in the Cabinet last week gave May a boost, meets other Cabinet Brexiteers to discuss strategy.

It was reported that Gove, Andrea Leadsom, Chris Grayling, Penny Mordaunt and Liam Fox will meet and try to force May into renegotiating elements of the draft.

The so-called “gang of five” have temporarily put aside their misgivings, but further resignations could prove fatal for the Prime Minister.

Meanwhile, May has warned her Tory opponents that rival Brexit withdrawal plans, including the so-called Norway and Canada models favoured by her hardline critics, would not solve the backstop issue.

In an interview yesterday, the Prime Minister said: "People say 'If you could only just do something slightly different, have a Norway model or a Canada model, this backstop issue would go away'. It would not. That issue is still going to be there.”

May appointed Stephen Barclay as her new Brexit Secretary, the third this year, but the role has been further downgraded as the Prime Minister will in future take sole control of negotiations on EU withdrawal.

The job of Barclay, a Leave supporter, will be limited to the domestic delivery of EU withdrawal, preparations for Brexit either with or without a deal and shepherding legislation through Parliament.

He said: "We now need to keep up the momentum to finalise the withdrawal agreement and outline political declaration and deliver a Brexit that works for the whole UK."

Party chairman Brandon Lewis said the Prime Minister is "prepared for anything", when asked on BBC Radio 4's Today programme if she was prepared for a leadership challenge.

He added: "I think that whatever deal, when we see various different organisations and groups talk about different ways of leaving the EU - Norway, Canada, all of these things - what we have to be clear about ... is all of those require a backstop."

In another development, Ireland's deputy premier has warned MPs to sign up to the Brexit agreement or risk crashing out of the EU without a deal.

Simon Coveney said people were "too quick" to write off May, saying she has shown "resilience, courage" and a "reality check" to Brexiteers in Westminster.

He warned it "will be difficult" to find an alternative deal that will prevent a hard border. "If we are forced into that situation we will have to look at ways in which that can be avoided but that will not be easy," he added.

"It is a far more sensible approach to support what is being negotiated over the last two years as a way that we know provides the guarantees that we have looked for and insisted on that there will be no physical border or infrastructure or checks or controls and that is an issue that goes beyond commerce and trade."