Inside the No 10 bunker, there has been heated discussion about whether a snap general election fronted by Theresa May remains a possibility.

But with the Conservatives plunging below Labour in the polls this weekend and the party’s split over Europe looking increasingly irreconcilable, there are growing warnings from Tory grandees that even entertaining such a course of action is deeply unwise.

“It was certainly being tested,” said one Downing Street adviser. “Some people weren’t exactly arguing in favour, but were saying it could be the least worst option.”

Stephen Parkinson, May’s political secretary and a former Vote Leave organiser, and Robbie Gibb, the Downing Street director of communications, were named as the main voices considering whether to take May’s deal to the people. But a No 10 source denied in the strongest terms that Gibb in particular was in favour of such action.

Suspicions that May is considering a snap poll were raised by her address to the public from No 10 lambasting parliament for frustrating Brexit, and money was spent on Facebook advertisements promoting her message.

Speculation was then dampened again by May’s promise to stand down if her deal was passed, with Conservative MPs reassured that she could not possibly lead a general election as a “lame duck” who had signalled that she was ready to hand over to a colleague for the second phase of negotiations.

But then the opinion resurfaced again in No 10 that she could carry on in power for longer by taking her deal to the public, pitching the Conservatives as the party of Brexit against a Labour party that would argue for a softer Brexit and only with a second referendum.

May’s decision to call a third futile vote on her deal last week then looked like an attempt to portray Labour as voting against the withdrawal agreement on 29 March – the date that would have been Brexit day.

One of the arguments is that the threat of a snap election is a useful tool to frighten some more Eurosceptic MPs into voting for May’s Brexit deal, but a small contingent in No 10 still think there is a genuine chance that she could win.

There is also the possibility that the party could be plunged into a general election by accident if May’s government falls in a vote of no confidence and parliament is unable to find an alternative leader with a majority within 14 days.

However, over the weekend, May was quickly confronted with warnings that the Tory party is in no way ready for an election, in terms of money, organisation, the backing of her own MPs or support in the country.

In no uncertain terms, the prime minister has been told by senior Conservative party figures that it would risk “annihilation” and Jeremy Corbyn being installed in No 10.

This is the stark reality that she is expected to present to cabinet on Tuesday morning, as it considers the various options to break the impasse in parliament and the Tory party.

Lord Hayward, the Conservative peer and election expert, said: “The prime minister has been given the message loud and clear that there should not be an election. If you are a Conservative MP with anything other than a massive majority, you do not want one.”

He said polls and byelection results suggested May’s address to the public lambasting MPs had initially not gone down badly, but any benefit of that had been lost by the indication that she would stand down if her Brexit deal was passed.

William Hague, the former Conservative leader, said on Monday night that an election would result in the party’s “ruin”.

Part of the problem appears to have been that No 10 was given hope about May’s chances with the public because of data that suggested she was not unpopular with the country. But senior Tories note there is a difference between voters feeling sorry for a prime minister struggling to deal with enormous Brexit difficulties and deciding that the Conservatives are the party they want to vote into government.

From cabinet ministers to senior backbench MPs, in both the leave and remain camps, there is widespread despair in the party that anyone in Downing Street could be considering such a path at such a time.

“It is nailed-on mad. But the mood in No 10 is desperate. They are in a bunker and in denial about how bad things are,” said one special adviser.

Several Downing Street advisers rejected the often repeated suggestion that they operate in a bunker and argued that their plan has always been about listening to the public.

A No 10 source said: “We have been trying to find a way to deliver the referendum result. But the point we keep making is that if parliament doesn’t want the deal or no deal, parliament has got to come to a decision about what it does want.

“The country, government and parliament has to find a way through. The pressure really needs to be on those people, and particularly the Labour party. They say they want to leave, but every single option is rejected.”

In public, May’s warnings that parliament is coming to the end of its ability to take a decision on Brexit have been interpreted as an oblique warning that a general election may be the only way out.

However, two people who have spent time with the prime minister recently conclude that she does not regard the idea of fighting another election with relish, even if it would give her a mandate to stay in power.

In fact, they say she is listening closely to the views of Gavin Barwell, her chief of staff, and “JoJo” Penn, the deputy chief of staff and her longterm adviser, who are of a softer Brexit persuasion than some of their colleagues and concerned about the impact of a snap election.

And one Tory MP pointed out that it might suit the prime minister to threaten an election in a last-ditch attempt to bring Eurosceptics to heel, but it would certainly not be good for her legacy to be the prime minister that not only lost a majority, mishandled Brexit and split the Conservative party for good, but handed the keys to No 10 to Jeremy Corbyn for a decade.

May’s top advisers

Robbie Gibb May’s influential director of communications is a former head of the BBC’s political team at Westminster, who is guided by his deep knowledge of the broadcast media and connections across the Conservative party. He is viewed as a firm Brexiter.

Stephen Parkinson He worked with May in the Home Office, so is a very trusted aide. He was subsequently instrumental in the ground war of the Vote Leave operation.

Gavin Barwell The chief of staff is a former MP who lost his seat in 2017 and was previously a strong remain supporter. He tweeted after the 2016 referendum: “Proud that my home town [Croydon] and the great city of which it is part rejected the politics of hate and division yesterday.”

Joanna Penn May’s most senior female adviser has been with her since the Home Office and is known to have the prime minister’s ear.

Philip May The prime minister’s husband is an investment manager for his day job but also part of her inner circle and a close adviser.