The prime minister’s room for compromise was narrowed this week by remarks from the DUP leader Arlene Foster

Theresa May is contemplating breaking with the Democratic Unionist Party to get her Brexit deal through parliament after relations between the parties worsened.

The prime minister is fighting on multiple fronts amid signs that some of her cabinet could walk out next week over the backstop, her insurance plan to keep the Northern Irish border open.

Intensive talks are under way between the DUP and the Tories over the relationship between Northern Ireland and mainland Britain after Brexit.

At the heart of the dispute is Mrs May’s plan to break a deadlock in talks with the European Union by permitting exports travelling between these areas to be checked. The DUP has flatly rejected this idea. Whitehall sources fear that the party has boxed itself