Around 50 Tory MPs have gathered to “openly” discuss how to remove Theresa May as Prime Minister, with the support of just 48 needed to trigger a vote of no confidence.

The MPs are from the 60-strong European Research Group (ERG), which is opposed to Mrs May’s “soft” Brexit and is currently publishing a series of papers on the benefits of a clean exit from the European Union (EU).

“We’ve just had an ERG mass meeting, 50 odd MPs present, where virtually the only topic of conversation for 40/50 mins was: how best do we get rid of her [Mrs May]? What’s the best way to use our letters?” a source told journalist Robert Peston.

Comments at the meeting reportedly included: “Everyone I know says she has to go,” as well as, “she’s a disaster”, and, “this can’t go on”.

Opposition to Mrs May’s Brexit plan has grown over Parliament’s summer recess and 80 MPs are reportedly considering voting against the so-called ‘Chequers’ plan.

They include high profile figures such as the former Tory leader Iain Duncan Smith, former international development secretary Priti Patel, and former Brexit minister Steve Baker.

The source continued: “You might think that this is usual far[e] for us, but it’s not! Not in the mass weekly meeting, never in what’s basically a public forum.

“The truly amazing thing was they spoke about it so openly, in such an unabashed way, even though they could see the Whips sneak sitting there.

“Really, really detailed discussion of the mechanics of how best you game the leadership election rules. And zero dissent.

“No one, in a room of fifty Tory MPs even raised a squeak of objection. Not even a murmured pretence as good form. Nor did anyone preface their remarks with any ‘sadly I’ve concluded formulae’.

“We were in the Thatcher Room to add piquancy.”

A separate source added: “It was truly mind-blowing. You felt the ground opening up under your feet. The most amazing thing was that no one even bothered to mime a pretence of regret.”

Earlier in the day, Tuesday, members of the ERG had also met in a committee room to present a paper arguing a ‘no deal’ Brexit will boost the UK economy by £1.1 trillion over 15 years and dismissing scare stories about food and drug shortages.

Mrs May’s Brexit plan proposes keeping the UK tied to all the bloc’s rules on goods, meaning the UK will remain severely restricted in its ability to strike new deals.

The key provision of the plan — keeping Britain in the single market for goods — was rejected publicly by European Commision President Jean-Claude Juncker Wednesday morning in his state of the union speech.

It has been called as the “worst of all worlds” and “Brexit in name only” by a former governor of the Bank of England and described as more unpopular that the poll tax by a pro-EU former Cabinet Minister.