Scotland and Northern Ireland are separated by just a few short miles of sea. But when it comes to access to abortion, they are divided by more than 150 years of history. While Scots women are able to access abortions on the same basis as their counterparts in England and Wales, Northern Irish women still face a near-total ban on the termination of pregnancy.

In 2014-15, only 16 women were able to have lawful abortions in Northern Ireland. By contrast, 833 Ulster women travelled to England or Wales and paid for terminations at private clinics. And despite being full and equal taxpayers, Northern Ireland-resident women have been barred from accessing free abortions in NHS hospitals in England, Wales and Scotland.

It was into this breach that Scotland’s first minister, Nicola Sturgeon, stepped last week when she told the Scottish parliament that she would explore the possibility of women and girls from Northern Ireland being able to access terminations through NHS Scotland. Her intervention has enraged the deeply conservative Democratic Unionist party (DUP), Northern Ireland’s largest party of government, but been welcomed by pro-choice and human rights campaigners in the region.

While healthcare has been a devolved matter in Scotland since the creation of the Scottish parliament, it was only in May this year that abortion law was handed over to Holyrood. It is against this backdrop that Sturgeon’s intervention has demonstrated leadership on behalf of Northern Irish women sorely lacking both at Stormont and Westminster. There is near unanimous support in the Holyrood parliament for keeping abortion provision for Scotland in line with the 1967 Abortion Act. The picture couldn’t be more different across the water.

As recently as February this year, the Northern Ireland assembly voted to keep the region’s abortion law as it is, refusing to legislate for abortion even in cases of rape, incest, or where the foetus has no chance of survival outside the womb. This was despite a Belfast high court finding, just two months previously, that Northern Ireland law breaches the European convention on human rights.

Meanwhile, the UK health secretary Jeremy Hunt has determined that the NHS in England must operate a residence-based system so that women who live in Northern Ireland are barred from accessing NHS abortion services in England, despite being UK citizens. This position is currently the subject of a legal challenge at the UK supreme court taken by a Northern Ireland teenager and her mother. They want women and girls from Northern Ireland to receive free abortions on the NHS in England.

The young woman at the centre of the case was 15 in 2012 when she and her mother travelled from Northern Ireland to Manchester and were asked to pay for a private termination. It is estimated that, with private clinic charges as well as the cost of travel and accommodation, a Northern Ireland woman needs to find anything between £400 and £2,000 to obtain a lawful abortion across the water in Britain – NHS care available for free to women in every other part of the UK.

Northern Ireland's politicians are being left behind by the people

Stephen Cragg, who is acting as QC for the mother and daughter, told the supreme court at a hearing earlier this month that women and girls like his client are “second-class citizens” who “live in the UK, but – unlike all other women and girls in the UK – they are at risk of the most serious criminal penalty if they procure an abortion in their own area”.

In Northern Ireland, any woman or girl who has an abortion deemed unlawful is liable for prosecution and could face a sentence of up to life imprisonment. Earlier this year a woman who had induced her own miscarriage by taking abortion pills obtained over the internet was found guilty under the 1861 Offences Against the Person Act and given a three-month suspended sentence. There are a number of other similar cases poised to come before the courts in Northern Ireland, including the prosecution of a mother who obtained the pills on behalf of her pregnant teenage daughter.

Despite all this, a majority of Northern Ireland’s politicians have set their face against reform. Comfortable in their self-designation as “pro-life”, they appear to be immune to criticism – even from the UN, whose human rights committee recently ruled that this part of the UK’s laws prohibiting and criminalising abortion constitute a human rights violation.

But, increasingly, Northern Ireland’s politicians are being left behind by the people. Independent polling published recently by Amnesty International showed that seven in 10 people want to see Northern Ireland’s harsh abortion laws changed, while more than half want to see abortion decriminalised altogether. The tens of thousands of people who are calling for abortion to be decriminalised also speak to that shift.

Sturgeon’s offer of possible help to Northern Irish women and girls should be a matter of deep embarrassment to ministers in Northern Ireland. Theresa May should match Sturgeon’s offer to stand up for Northern Irish women abandoned by their own politicians. When it comes to the human right to healthcare, lines on a map should be no barrier.