THERESA May is defying calls from inside and outwith the Tory Party to "equalise" the law on abortion in Northern Ireland following the Irish referendum result, insisting it is a devolved matter for Stormont.

The Prime Minister tweeted her congratulations to the campaign to reform abortion law in the Irish Republic, saying it was an “impressive show of democracy, which delivered a clear and unambiguous result”.

Last week, Ireland voted by two to one to overturn a 35-year ban on terminations.

The result means Northern Ireland is now the only part of the British Isles where abortion is on the whole illegal. Currently, a woman can only end her pregnancy there if her life is in danger or if there is a risk of permanent and serious damage to her health.

A No 10 source said the Government’s position was that “this is a matter for Northern Ireland and for the assembly to decide upon”. There has been no government at Stormont for over a year.

Rory Stewart, the Justice Minister, also insisted: "It isn't the job - and it would be very, very dangerous - for British politicians to be seen to be telling people in Northern Ireland how to vote."

Arlene Foster, the leader of the Democratic Unionists, made clear Ireland’s referendum result had “no impact” on law in Northern Ireland and stressed how it was for the devolved assembly to decide on abortion.

Noting how the DUP was a pro-life party, she criticised the reaction of pro-reform campaigners, saying: “It is an extremely sensitive issue and not one that should have people taking to the streets in celebration.”

However, politicians north and south of the border called for the law to be “equalised” across the UK; one way or another.

Penny Mordaunt, the International Development Secretary and Minister for Women and Eqaulities, said the referendum signalled an "historic and great day for Ireland" and a "hopeful one for Northern Ireland," adding: "That hope must be met."

Four former holders of the equalities brief - Amber Rudd, Justine Greening, Nicky Morgan and Maria Miller – backed Ms Mordaunt’s view while Anne Milton, the UK Education Minister, described the current situation in Northern Ireland as “anomalous” and suggested she would back liberalisation on a free vote.

Dawn Butler, Labour’s Shadow Equalities Minister, declared: “This is an injustice. No woman in the UK should be denied access to a safe, legal abortion.

“We call on the Government to support legislation to extend abortion rights to Northern Ireland. Labour is looking at legislative options for achieving this and urge the Conservatives to work with us to make it law,” she added.

Her colleague Lesley Laird, the Shadow Scottish Secretary and expected to become Scottish Labour’s Deputy Leader on Monday, said if the PM was considering staying in alliance with the DUP, then she “needs to use this opportunity to stand up for women in Northern Ireland and ensure that abortion law is now equalised across the UK”.

Jo Swinson, the deputy Liberal Democrat leader, said it was simply unacceptable for women in Northern Ireland to continue to be treated in a “cruel way; lacking the protections and access to healthcare that women have had in other parts of our country”.

She added: “The UK Government must act to ensure this situation is swiftly remedied; women in Northern Ireland deserve to be trusted too."

The SNP’s Joanna Cherry, speaking in a personal capacity, said she was pleased about the outcome of the referendum but stressed devolution must be respected.

She argued that if Westminster were to legislate, then it should be for a referendum on abortion in Northern Ireland.

The Edinburgh MP added: “Whatever happens Theresa May’s pact with the DUP should not be allowed to prevent women in Northern Ireland from enjoying the same rights as women elsewhere in the island of Ireland and across the UK."