Two Conservative MPs have resigned party roles in opposition to Theresa May’s Chequers Brexit policy.

Maria Caulfield and Ben Bradley resigned as vice chairs of the Conservative Party saying that their seats will be lost and Jeremy Corbyn will become Prime Minister unless the party delivers Brexit.

Ben Bradley, who voted Remain, represents the constituency of Mansfield which voted over 70% Leave. Maria Caulfield, a Brexiteer, represents the constituency of Lewes which voted Remain.

Both represent marginal seats. Ben Bradley’s seat had previously voted Labour for a century and Maria Caulfield’s had been represented by the Liberal Democrats. Both say their seats will be lost unless the party delivers Brexit.

In their resignation letters Bradley and Caulfield blame Theresa May’s insistence on a backstop in Northern Ireland for undermining the opportunities of Brexit. Caulfield said it was “neither necessary or constructive for the future prosperity of the UK” and Bradley called it a “barrier to the kind of wide-ranging free-trade agreement with the EU that many in our party and the country would like to see“.

These resignations follow that of the Foreign Secretary, Boris Johnson, the Brexit Secretary, David Davis and Brexit Minister Steve Baker after Theresa May made it clear that members of the government would have to back her change of Brexit policy.