Brexit debacle would cost UK PM Theresa May her job in an election, poll analysis shows

British opposition leader Jeremy Corbyn is on course to sweep into No 10 after Theresa May failed to deliver on her promise to take the UK out of the EU by March 29, a major polling analysis reveals.

The Conservatives would lose 59 seats in the event of a general election, making Labour the largest party in the Commons, according to an exclusive poll of polls for The Sunday Telegraph.

Iain Duncan Smith, the former Conservative leader, and Amber Rudd, the Work and Pensions Secretary, would be at "high risk" of being voted out.

Experts said the dramatic fall in support was down to anger among Tory voters "at the Government's failure to deliver Brexit". Prof Sir John Curtice, president of the British Polling Council, said Leave supporters had been "drawn back to either Ukip or Nigel Farage's newly launched Brexit party".

Separately, amid growing calls for May to resign, Conservative Party lawyers potentially opened the door for MPs to formally oust the Prime Minister within months, with officials advising the influential 1922 Committee that the panel could rewrite the rules currently preventing MPs from mounting more than one attempt to oust a leader per year.

  

The extraordinary move emerged as two past chairmen of the backbench committee declare, in an article for The Sunday Telegraph, that the panel could alter the rules that prevent backbenchers from triggering another vote of no confidence in May until December, after she won a previous vote last year by 200 to 117.

Last night, Sir Graham Brady confirmed: "It is my understanding that the rules could in future be changed by the agreement of the 1922 executive." He added that it was "less certain that it would be possible to change the rules during the current period of grace which was initiated with the triggering of a confidence vote on Dec 12 last year."

An Electoral Calculus poll of polls of 8561 people surveyed between April 2 and 11 after May's intended exit date found that following an immediate general election, Labour would become the largest party in the Commons.

It would win 296 seats against 259 for the Tories. Corbyn could then lead a government propped up by the SNP. Other Tories who face losing their seats include Zac Goldsmith, Justine Greening and Stephen Crabb.

Martin Baxter, the Electoral Calculus founder, said: "Theresa May is discovering why David Cameron really held the referendum. It wasn't to placate his own Eurosceptic MPs, instead it was to stop Conservative voters defecting to pro-Brexit parties. That process seems to have restarted and the Conservatives are beginning to suffer."

Writing in The Telegraph, Sir John states: "Much of this drop reflects disappointment among Leave voters."

May told MPs last month that should would stand down once she had secured the UK's exit from the EU. Now she faces mounting calls by MPs and senior grassroots figures to name a date for her departure as it appeared that the UK would have to participate in elections to the European Parliament. Dozens of local Conservative chairmen are also now joining a strike against campaigning in the elections.

May is holding talks with Labour in an attempt to secure a compromise deal involving a deeper EU customs arrangement. Downing Street said ministers would now form working groups with senior Labour figures.

Writing in this newspaper, Lord Spicer and Lord Hamilton of Epsom, who chaired the 1922 committee successively from 1997-2010, state: "Conservative MPs are responsible for their party. If they wish [to] change these rules there is nothing standing in their way."

Sheryll Murray, a member of the 18-strong executive, confirmed that the issue was likely to be discussed at the executive's next meeting. A source said it would seek legal advice on whether it could alter the rules to cut short the 12-month grace period afforded to May, if the panel decided to act. The advice would determine if any changes would apply only to future votes, to avoid a legal challenge.

Leadership contenders are constructing campaigns in earnest. Mel Stride, a Treasury minister who backs Gove, has shown MPs pie charts purporting to show that he would have broad support across the country. One MP claimed Stride said the data showed Gove as the only candidate who could beat Boris Johnson.

At a US reception on Friday, Philip Hammond said: "I think I may be the only member of the 320-strong Parliamentary Conservative Party who isn't ... standing or potentially standing."