Three MPs have quit the Conservative Party in protest at Prime Minister Theresa May's Brexit plans.Sarah Wollaston, Heidi Allen, and Anna Soubry have joined the breakaway Independent Group, which seven Labour MPs founded on Monday."Brexit has re-defined the Conservative Partyundoing all the efforts to modernise it," a statement from the MPs said.May said she was "saddened" by the decision.LONDONThree Conservative MPs have resigned from the party to join a new breakaway group in protest at Prime Minister Theresa May's Brexit strategy and the state of the Tory party.The MPs Sarah Wollaston, Heidi Allen, and Anna Soubry on Wednesday said they had resigned from the Conservatives and joined the new Independent Group, which was started Monday by seven MPs who resigned from Labour this week and later joined by an eighth.Business Insider reported on Tuesday that the Conservative trio were set to quit the party despite friends' pleading with them to stay.Writing to May to inform her of their decision, they said the Conservative government had bowed too far to the demands of the Brexit-supporting European Research Group of Tory MPs and the Democratic Unionist Party."We no longer feel we can remain in the Party of a Government whose policies and priorities are so firmly in the grip of the ERG and DUP," they wrote."Brexit has re-defined the Conservative Partyundoing all the efforts to modernise it. There has been a dismal failure to stand up to the hard-line ERG which operates openly as a party within a party, with its own leader, whip and policy."Why did they jump'Allen, Wollaston, and Soubry are joining a new bloc of MPs who are principally united by two things: disillusionment with the leadership of the Labour and Conservative parties, and opposition to Brexit.Many of the Independent Group's members are leading supporters of the People's Vote campaign for a second Brexit referendum, having repeatedly implored the government to pursue a softer exit from the European Union.May's refusal to adopt these positions, plus a widely shared belief that they would soon be ousted by an increasingly hardline, pro-Brexit party membership, led the trio to walk away.An ally of Allen told Business Insider that they had emailed her earlier this week, "begging her to stay" in the party.Figures in the "moderate" wing of the Tory Party are furious with Conservative Campaign Headquarters for failing to prevent former UK Independence Party supporters and hardline Brexiteers from flooding local parties nationwide.Allen, Wollaston, and Soubry plus other Conservative MPs had all been threatened with deselection by party members.May: 'I am saddened by this decision'"I am saddened by this decisionthese are people who have given dedicated service to our party over many years, and I thank them for it," May said in a statement."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."I am determined that under my leadership the Conservative Party will always offer the decent, moderate and patriotic politics that the people of this country deserve."Join the conversation about this storyNOW WATCH: How Apple went from a $1 trillion company to losing over 20% of its share price Click here to read full news..