South Cambridgeshire MP Heidi Allen is one of three Conservatives who have defected to the new Independent Group this morning.
Mrs Allen, along with fellow Tory MPs Anna Soubry and Sarah Wollaston, joined the group of Labour politicians after seven MPs split from their party on Monday.
In a letter to Prime Minister Theresa May explaining their decision, the Conservative trio wrote: “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 European Research Group and Democratic Unionist Party.
“Brexit has redefined the Conservative Party – undoing 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.
“We also reject the false binary choice that you have presented to Parliament between a bad deal and a no deal.
“Running down the clock to March 29 amounts to a policy of no deal and we are not prepared to wait until our toes are at the edge of the cliff.”
Reacting to the announcement, Mrs May said: “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.”
MPs Chuka Umunna, Mike Gapes, Luciana Berger, Ann Coffey, Angela Smith, Gavin Shuker and Chris Leslie defected from Labour to form the group on Monday, with Joan Ryan joining them today.
“We intend to sit as independents alongside The Independent Group of MPs in the centre ground of British politics,” said the former Tory trio.
“There will be times when we will support the government.
“But we now feel honour bound to put our constituents’ and country’s interests first.”
Mrs Allen became South Cambs’ MP during the 2015 General Election and also stood for the role of Cambridgeshire and Peterborough mayor – but she failed to progress to the final round of the internal selection process after a vote by local party members in January 2017.
She was re-elected in the snap General Election of 2017, and has strongly advocated remaining in the EU – calling for a People’s Vote over Brexit.