Theresa May has risked triggering a fresh rebellion from Tory MPs after she said she would not try to remove the backstop plan from the Brexit deal.

Speaking in Northern Ireland on Tuesday, the prime minister said she was not proposing to strike an agreement that did not “contain that insurance policy for the future”.

“What parliament has said is that they believe there should changes made to the backstop,” she said.

May will meet European Council president Donald Tusk in Brussels on Thursday afternoon to try and hammer out a revised deal after MPs rejected her initial plan.

Rebel MPs from both sides of the Conservative Party’s Leave/Remain divide have been holding talks to develop ideas for “alternative arrangements” to replace the backstop.

But the EU has so far rejected any suggestion the Withdrawal Agreement signed in December could be reopened. 

Following the prime minister’s comments today, Brexiteers appeared split over whether the backstop had to be replaced or whether a unilateral exit mechanism would be enough to win their support.

One senior Tory MP told HuffPost UK hard Brexit colleagues could only back the deal if the backstop was removed entirely and replaced with “alternative arrangements”.

There would also have to be no checks between Northern Ireland and the Irish Sea and Britain must be able to leave the alternative arrangement of its own accord, the MP said.

However a separate Brexiteer source said Tories could accept the backstop if there was a clear unilateral exit mechanism, which appears a more likely compromise with the EU.

It could take the form of a two-year exit mechanism, similar to Article 50 for leaving the EU, they said.

This would have to be backed up by written legal advice from the Attorney General Geoffrey Cox stating that the UK would not be trapped in the backstop.

A statement to the House of Commons would not be enough, they added, pointing out that Lord Goldsmith comments on the legal case for the Iraq War to the Lords were far more political and less explicit than his written advice for the government, the source added.