Heidi Allen, Anna Soubry and Sarah Wollaston claim "hard-line anti-EU" MPs now run the Conservatives.
The foreign secretary says a "small but important" change to backstop could persuade MPs to back deal.
Theresa May clashed with Jeremy Corbyn over Brexit - here are the key bits.
Ex-Militant man was only readmitted to the party on Monday, more than 30 years after being expelled.
Labour could lose control of Brighton and Hove City Council after Anne Meadows defects to the Tories.