LONDON - Three Conservative MPs have quit the party to join the Independent Group in the British Parliament. Anna Soubry, Heidi Allen, and Sarah Wollaston resigned from the ruling party on Wednesday over the government’s handling of Brexit.

The pro-EU legislators have been long-standing critics of May’s strategy to take Britain out of the European Union and will sit with the Independent Group, formed by former Labour MPs this week.

In a letter to British Prime Minister Theresa May, the trio accused the Conservative Partyof abandoning the political centre ground, and said, “The final straw for us has been this government’s disastrous handling of Brexit.” 

With Britain’s departure from the EU due on March 29 and no deal yet agreed on divorce terms, the three legislators accused the government of “recklessly marching the country to the cliff edge of no deal.”

The move is a blow to Prime Minister May’s attempts to unite her party around her Brexit plans. “I am saddened by this decision,” May said in a statement and defended her strategy, adding that the Brexit process was never going to be easy.

“But by delivering on our manifesto commitment and implementing the decision of the British people, we are doing the right thing for our country.” The Independent Group was formed by seven ex-Labour MPs, including Chuka Umunna and Luciana Berger, and was joined by an eighth MP on Tuesday. They said they quit the Labour Party over its Brexit policy and failure to tackle anti-Semitism. Labour leader, Jeremy Corbyn, said he was disappointed that the MPs quit and called on party members to unite.

“I am disappointed that these MPs have felt unable to continue to work together for the Labour policies that inspired millions at the last election and saw us increase our vote by the largest share since 1945,” he said.

None of the MPs who have left their parties have resigned their seats, meaning by-elections will not be held to replace them and they will continue to represent their constituencies in parliament until at least the next election.

Both Labour and the Conservatives have experienced bitter infighting over a number of issues, but primarily Brexit.

May and Corbyn have insisted that the result of the 2016 referendum on EU membership should be respected and have so far ignored calls to hold a second referendum.

The prime minister has repeatedly failed to get her preferred agreement to leave the EU passed in parliament and barring an extension, the UK will crash out of the bloc with no deal.

That would mean trading with the bloc and other countries on World Trade Organization rules, which analysts believe will cause huge economic disruption to the country.

The Independent Group was formed on Monday by the erstwhile Labour MPs, who include Chuka Umunna, Luciana Berger and Chris Leslie. Joan Ryan became the eighth MP to quit Labour and join the group on Tuesday night. The MPs said they felt it necessary to leave Labour because of the leadership’s Brexit policy and failure to tackle antisemitism in the party.

In a statement, Theresa May said she was disappointed by the decision of the three to leave her party. “I am saddened by this decision. These are people who have given dedicated service to our party over many years, and I thank them for it,” she said. “Of course, the UK’s membership of the EU has been a source of disagreement both in our party and our country for a long time. Ending that membership after four decades was never going to be easy. But by delivering on our manifesto commitment and implementing the decision of the British people we are doing the right thing for our country. And in doing so, we can move forward together towards a brighter future.”

The prime minister added that she was determined the Conservatives would still offer the “decent, moderate and patriotic politics that the people of this country deserve”.

At the press conference all three of her departing MPs said they had lost faith in the politics of compassionate Conservatism, championed by David Cameron, which had drawn them to the party.

Allen said she had been inspired by Cameron and the party’s “competence and compassion” but said she had found herself “so often going over the top, fighting for compassion in our welfare system” and that the party had “deepened rather than fixed” people’s suffering.

Wollaston, chair of the health select committee, said she had originally hoped May would be able to change things. “The prime minister hasn’t delivered on the pledge she made on the steps of Downing Street to tackle the burning injustices,” she said.

The group said they intended to sit as independents, like the eight MPs who have quit Labour. “There will be times when we will support the government, for example, on measures to strengthen our economy, security and improve our public services,” the three MPs said in their letter. “We will continue to work constructively, locally and nationally, on behalf of our constituents.”

Before their press conference, Soubry, Wollaston and Allen entered the chamber of the Commons together and went to their new colleagues on the opposition benches. All 11 MPs sat together during an occasionally surreal prime minister’s questions, where both May and Corbyn studiously ignored the defections in their exchanges.

Tory sources suggested the Conservative associations of the three MPs would be free to start selecting new Conservative candidates. A No 10 spokesman said, however, that it was not insisting the MPs fought byelections and that it was hoped one day that the trio would return.

Phillip Lee, who quit as a justice minister to back a second referendum, had been tipped as another potential Tory departure, but he ruled out the move Wednesday morning. Sam Gyimah, who also resigned as a minister over the government’s position on Brexit, ruled out joining the Independent Group on Tuesday.

Others who have previously been critical of the Tory approach to Brexit, including Nick Boles and Antoinette Sandbach, both ruled out quitting the party.

A Labour source said the defections meant “the Independent Group has now become a Tory establishment coalition”. The source added: “What unites the 11 MPs is their business-as-usual support for austerity, corporate tax cuts and big-money corrupting politics.”