The Democratic Unionist party has said it would vote against any plan which saw checks on goods coming into Northern Ireland from the mainland UK, in a serious rebuke of Theresa May.

Nigel Dodds, the DUP's leader in Westminster told a Tory party fringe that if the UK came to an arrangement which saw Northern Ireland in a different customs arrangement than the rest of the United Kingdom, then “We will vote against it. We will vote for our red lines,”.

“In Northern Ireland we’ve grown up with a lot of fears and issue that we’ve faced, frankly being afraid of what Theresa May may do is not one of my biggest fears,” said Dodds.

“The deal on the future relationship will have to be crystal clear and not a fudge, we won’t settle for any vague outline of a future relationship in exchange for a backstop, that is simply not going to happen,”

The Democratic Unionist Party's ten MPs give Theresa May her theoretical governing majority in parliament, but if they were to vote against the final deal it would be practically impossible for May to pass any agreement through the House of Commons.