Up to 20 Tory MPs, most of them former ministers, have discussed plans to break away and fight the next general election as independent Conservatives opposed to a no-deal Brexit.

In a move that would send shockwaves through the party, senior Tories against a hard Brexit have privately vowed to walk out if Boris Johnson makes them sign a public pledge to support a no-deal manifesto in a snap election. The group has already been dubbed the “rebel alliance”, echoing the Star Wars films’ resistance movement.

Potential rebels Philip Hammond, David Gauke, Greg Clark, Rory Stewart and Justine Greening have held discussions about launching a new Tory campaign organisation opposed to no deal.

But the rebels have also drawn up contingency plans in case Johnson