Theresa May might not seek to reopen the Brexit withdrawal agreement as she tries to secure changes to the controversial Irish border backstop, a cabinet minister has suggested in comments which risk infuriating Tory eurosceptics.

Culture Secretary Jeremy Wright stressed that the “mechanism” to change the backstop does not matter.

But it comes after senior Brexiteer Steve Baker warned in WhatsApp messages leaked to the Sunday Times that anything other than removing the backstop from the withdrawal agreement would see the Tories “just grind towards a party split”.

Brexiteers vehemently oppose the backstop because they fear it could trap Britain permanently in a customs union with the EU, leaving it unable to strike its own free trade deals around the world after Brexit.

They want the withdrawal agreement, which is the legally binding part of the Brexit deal that MPs are being asked to approve, changed to make clear that this will not happen.

But Wright said there may be another way of reassuring Tories that the backstop will not be indefinite without having to reopen the current legal text, suggesting the prime minister could seek a codicil or addendum to the deal.

disputed Irish border backstop, a cabinet minister has suggested in comments which risk infuriating Tory eurosceptics.

Culture Secretary Jeremy Wright stressed that the “mechanism” to change the backstop does not matter.

But it comes after senior Brexiteer Steve Baker warned in WhatsApp messages leaked to the Sunday Times that anything other than removing the backstop from the withdrawal agreement would see the Tories “just grind towards a party split”.

Brexiteers vehemently oppose the backstop because they fear it could trap Britain permanently in a customs union with the EU, leaving it unable to strike its own free trade deals around the world after Brexit.

They want the withdrawal agreement, which is the legally binding part of the Brexit deal that MPs are being asked to approve, changed to make clear that this will not happen.

But Wright said there may be another way of reassuring Tories that the backstop will not be indefinite without having to reopen the current legal text, suggesting the prime minister could seek a codicil or addendum to the deal.

The former attorney general told the BBC’s Andrew Marr Show: “I think what’s obvious is that Parliament, and I think probably people well beyond Parliament, are concerned about the potential indefinite nature of the backstop – that’s what we’ve got to do something about.

“If this is the only way of doing it then that’s the way we will pursue. If there are other ways of doing it that are just as effective that perhaps we haven’t yet explored then we will do that too.”

He continued: “I don’t think it’s the mechanism that matters, it’s the objective: if you can get to a place where the potential longevity of the backstop, the potential that the backstop lasts forever can be adequately dealt with, that’s what we’re all seeking to do.

“That’s what Parliament has been very clear that it wants, it will back this deal if we can do something about the backstop.”

The prime minister last month promised to secure “legally binding change to the withdrawal agreement”, potentially including a backstop time limit, unilateral exit mechanism or a replacement with “alternative arrangements”.

The EU has so far refused to reopen the text of the withdrawal agreement and speculation is rife that it may instead offer a codicil, addendum, or additional protocol to try and convince the UK the backstop will not be permanent.

Baker has however told scores of MPs in the Brexiteer Tory European Research Group that it has to “insist” the backstop is removed, otherwise the negotiations are a “complete waste of time”.

Speaking to the Sunday Times, he added: “What will it take for the PM to accept that we will not accept the backstop in its current form?”

May on Saturday night issued a desperate plea to Conservative MPs to unite and deliver on Brexit, urging her party to “move beyond what divides us” and sacrifice “personal preferences” for the national interest.

Mrs May, in a letter to all 317 Conservative MPs after her Brexit plans suffered a humiliating Commons defeat on Valentine’s day, said the result was “disappointing” but vowed that the government would continue its work to secure changes to the Irish border backstop.

She announced that she will return to Brussels for further talks with European Commission president Jean-Claude Juncker next week, and revealed plans to speak to the leaders of every EU member state over the coming days.

Meanwhile, Brexit Secretary Stephen Barclay will meet the EU’s chief negotiator Michel Barnier on Monday to discuss the proposals of the alternative arrangements working group of Tories, who have been probing how the backstop might be replaced with measures put forward in the so-called Malthouse compromise.

Attorney General Geoffrey Cox will set out what changes would be required to eliminate the legal risk of being indefinitely trapped in the controversial Irish backstop in a speech on Tuesday.