A Conservative MP, who this week quit the European Research Group of Conservative Eurosceptics, has said opponents of the deal could now see the party "decimated."

Daniel Kawczynski told Business Insider: "These ERG MPs are holding us to ransom. If this continues as it is the Conservative party will be decimated."

He accuses ERG members of holding sexist views about the prime minister.

The ERG, which is chaired by Conservative MP Jacob Rees-Mogg, has helped defeat Theresa May's deal three times.

LONDON — Conservative MPs who have led the opposition to Theresa May's Withdrawal Agreement now risk causing the party to be "decimated" at the polls, a former member of the hardline pro-Brexit European Research Group has told Business Insider.

Daniel Kawczynski MP, who quit the group this week, told Business Insider that: "These ERG MPs are holding us to ransom. If this continues as it is the Conservative party will be decimated. Who the hell is standing up to them? They are out of control."

Speaking to Business Insider, Kawczynski said "recalcitrant MPs" in the ERG were "destroying the reputation of the Conservative party."

"If this national humiliation goes on and we don't get this deal across the line, we will be punished, and we will lose credibility for a generation," he said.

He accused members of the group of showing "a huge amount of arrogance" and of being "millionaires in safe seats who think they will be cushioned from any catastrophic fall-out" from leaving with no deal.

He also accused his former colleagues of holding sexist views about the prime minister.

"I think there's some misogynism there. There's some at play," he said.

The MP for Shrewsbury is a committed Brexiteer who voted against the prime minister's withdrawal agreement twice and called on the Polish government to veto any extension of Article 50.

However he subsequently voted for May's deal on the third time of asking and then resigned from the ERG caucus of Eurosceptic Tory MPs on Wednesday after claiming opponents of the deal were now "endangering" Brexit.

He called for a fourth vote on the prime minister's deal which was attached to a confidence vote, meaning any Conservative MP who voted against the deal would immediately lose the party whip.

The ERG's deputy chairman Mark Francois insisted this week that members of the group will continue to oppose the deal.

He told BBC Newsnight: "The withdrawal agreement keeps us in the European Union, that's why we've always been so against it."

The ERG was founded in the 1990s in opposition to former prime minister John Major's decision to sign the EU Maastricht Treaty.

It has been the leading vehicle for criticism of the Prime Minister's Brexit deal, with votes from its members helping to see it defeated three times by parliament.