The UK's highest court is to rule on a legal battle for women from Northern Ireland to receive free abortions on the NHS in England.
Supreme Court justices in London will announce their decision in a case brought by a mother and daughter.
The 20-year-old woman at the centre of the appeal was 15 in October 2012 when she and her mother travelled from Northern Ireland to Manchester and was told she had to pay hundreds of pounds for a private termination because she was excluded from free abortion services.
They originally lost their action in the High Court in London in May 2014 when a judge ruled that the exclusion was lawful.
The judge concluded that the Health Secretary was entitled to adopt a residence-based system so that women resident in Northern Ireland are not entitled to benefit from NHS abortion services in England, even though they are UK citizens.
The mother and daughter, who cannot be named for legal reasons, suffered a further defeat at the Court of Appeal in 2015.
The Supreme Court's deputy president Lady Hale and four other justices are ruling on their challenge against that earlier decision.
During the Supreme Court proceedings last year, the justices heard submissions that women and girls in need of abortion services in Northern Ireland were being treated as "second-class citizens".
Stephen Cragg QC, for the mother and daughter, said they were in an "anomalous" position.
He told the court: "They 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."
The QC pointed out that, "unlike all other women and girls in the UK", they "cannot access abortion services through the NHS free of charge", adding: "In terms of reproductive rights, they are second-class citizens."
He said abortion has remained unlawful in Northern Ireland "in all but a tiny number of extreme cases".
Contesting the challenge, Jason Coppel QC, for the Government, submitted that it was not irrational for the provision of non-emergency healthcare to be divided between the different countries of the UK according to the place of residence of the patient.