Scores of MPs across the Commons have already indicated they are prepared to act to rewrite the current legislation given the absence of a devolved administration in Stormont.

But the prime minister faces a political headache over the issue because her fragile administration depends on the support of her DUP allies – who strongly oppose any reform to Northern Ireland’s abortion laws.

A number of senior Conservatives have called for a free vote on the issue.

Sign up to our daily newsletter The i newsletter cut through the noise Sign up Thanks for signing up! Sorry, there seem to be some issues. Please try again later. Submitting...

A woman sells badges at Belfast City Hall yesterday during a People Before Profit protest calling for provision of abortion in Northern Ireland

And Lord Morrow – who has been chairman of the DUP for over a decade – said the prime minister would face “consequences” if she permitted her MPs to vote in favour of any legislation which sought to liberalise abortion laws in the Province.

When asked by the News Letter if he thought the DUP would collapse the government over the issue, Lord Morrow replied: “If she allowed the Tory party to have a free vote on this then she would have to accept the consequences.

“I think it is something she would regret. But it is not something I think she has any intention of doing. Why would she risk losing the support of the DUP? She would not be foolish enough to do that.”

In contrast, a statement issued by the DUP head office did not clarify whether the issue would be a red line for the party.

Theresa May is under pressure on all sides to allow MPs a free vote on reforming Northern Irelands abortion laws

A DUP spokesperson said: “The areas covered by the confidence and supply agreement are detailed in the document agreed between the DUP and Conservative Party in 2017.

“The Conservative Party does not apply any whip on votes relating to the issue of abortion. The DUP is a pro-life party and we will continue to articulate that position.

“Abortion legislation in Northern Ireland is a matter for the Northern Ireland Assembly and we put no preconditions upon the return of devolution.”

Meanwhile, DUP MLA Jim Wells also thought it was unlikely the PM would jeopardise her confidence and supply arrangement with the DUP.

Lord Morrow said there would be consequences for Theresa May if she allowed a free vote

“I think if Theresa May was going to pick a battleground against the DUP it wouldn’t be this one,” the South Down MLA said.

“The government requires the DUP votes when it comes to getting Brexit through. There have been 54 votes on Brexit over the past year and 49 of them have been won by 10 or fewer votes, so it indicates our DUP MPs are playing an absolutely critical role in delivering the will of the people.

“There are three crucial votes on Brexit coming up and the Tories need the DUP on board to get them through.

“I’d be fairly confident the prime minister won’t want to touch this particular issue at the minute.”

Downing Street has said it believes that any reform in Northern Ireland “is an issue for Northern Ireland”, a source said, adding “it shows one of the important reasons we need a functioning Executive back up and running”.

DUP leader Arlene Foster said: “The legislation governing abortion is a devolved matter and it is for the Northern Ireland Assembly to debate and decide such issues.

“Some of those who wish to circumvent the Assembly’s role may be doing so simply to avoid its decision.

“The DUP is a pro-life party and we will continue to articulate our position.”

The forthcoming Domestic Abuse Bill promised by ministers could be used as a vehicle for MPs hoping to change the law in Northern Ireland.

In a sign of the pressure from within Mrs May’s own party, Education Minister Anne Milton suggested she would back liberalisation if there was a free vote.