Theresa May is under mounting pressure to lift Northern Ireland's abortion ban after MPs were granted an emergency debate on the issue.

House of Commons Speaker John Bercow approved Labour MP Stella Creasy's request for the debate, which will take place on Tuesday.

It adds to pressure on the prime minister following calls from her own MPs for reform of the law. Around 30 Conservatives stood in support of Ms Creasy's request, including ministers Penny Mordaunt, the international development secretary, who also holds the women and equalities brief, and Northern Ireland secretary Karen Bradley.

Abortion is currently allowed in Northern Ireland only if the mother's health is at risk. Calls for reform grew louder following the Republic of Ireland voting in a referendum to scrap its own abortion ban.

In addition to Ms Mordaunt, other senior Conservatives including Sarah Wollaston, the chair of the Commons health committee, and Justine Greening, the former education secretary, have also backed reform.

The debate called by Ms Creasy relates to repealing the 1891 Offences Against the Person Act (Oapa), which outlawed abortion.

The Walthamstow MP told the Commons: "The impact of the Irish referendum has been felt around the world. 2.1 million people voted, of which 1.4 million voted to repeal article 8, which prevents abortion. In doing so, they have thrown a spotlight on the situation in Northern Ireland, where a million women are affected."

She added: "Devolution, even if functioning, does not relieve this place of our responsibility to uphold human rights, whether in Northern Ireland or elsewhere."

Ms Creasy said repealing Oapa would allow Northern Ireland to decide whether to retain its ban on abortion, saying: "Repealing Oapa gives us the opportunity both to respect devolution and to respect women."

Northern Irish women protesting anti-abortion laws take illegal pills Show all 8 1 /8 Northern Irish women protesting anti-abortion laws take illegal pills Northern Irish women protesting anti-abortion laws take illegal pills Campaigners intervene after police try to lead away one of the three women (centre with sunglasses) who publicly took an abortion pill during a demonstration outside Belfast's Crown and High Courts, where counter-demonstrations were held by both sides of the Northern Irish abortion argument. PA Northern Irish women protesting anti-abortion laws take illegal pills Police officers watch on from close by as abortion rights campaign group ROSA, Reproductive Rights Against Oppression, Sexism and Austerity hold a protest in Belfast Getty Northern Irish women protesting anti-abortion laws take illegal pills Eleanor Crossey Malone takes an abortion pill as abortion rights campaign group ROSA, Reproductive Rights Against Oppression, Sexism and Austerity distribute abortion pills Getty Northern Irish women protesting anti-abortion laws take illegal pills Ruth Coppinger TD addresses the crowds outside Belfast's Crown and High Courts where counter-demonstrations were held by both sides of the Northen Irish abortion argument. PA Northern Irish women protesting anti-abortion laws take illegal pills Eleanor Crossey Malone displays an abortion pill packet after taking a pill Getty Northern Irish women protesting anti-abortion laws take illegal pills Protestors dressed as hand maidens stand as abortion rights campaign group ROSA, Reproductive Rights Against Oppression, Sexism and Austerity distribute abortion pills from a touring bus Getty Northern Irish women protesting anti-abortion laws take illegal pills An unidentified woman takes an abortion pill as abortion rights campaign group ROSA, Reproductive Rights Against Oppression, Sexism and Austerity distribute abortion pills from a touring bus Getty Images Northern Irish women protesting anti-abortion laws take illegal pills A robot drone delivers abortion pills as abortion rights campaign group ROSA, Reproductive Rights Against Oppression, Sexism and Austerity distribute abortion pills Getty

Concluding her speech, she said: "By repealing Oapa we, as the UK Parliament, can show women across the UK we trust them all with their own healthcare, wherever they live.

"I ask members to stand up with me and join in saying 'this is the 21st century'."

Downing Street has previously insisted the issue was a matter for Northern Irish politicians.

Ms May's spokesperson said last week: “This is a devolved matter. It is important to recognise that the people of Northern Ireland are entitled to their own process which is run by elected politicians.

“Our focus is restoring a democratically accountable devolved government in Northern Ireland so that locally accountable politicians can make decisions on behalf of the public they represent.”

The issue creates a major headache for Ms May because the Democratic Unionist Party (DUP), whose votes she relies on in Parliament, are strongly opposed to abortion and certain to strongly resist any move towards legal reform.

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