The case of two Catholic midwives fighting for the legal right to avoid any involvement in abortion procedures will be heard at the UK's highest court.

Mary Doogan and Concepta Wood, who are conscientious objectors to the process, won a challenge before three appeal judges at the Court of Session in Edinburgh in April.

Their victory followed a ruling against them last year in their action against NHS Greater Glasgow and Clyde.

In the latest round of the battle, Supreme Court justices in London are to hear an appeal by the health authority at a date to be fixed.

As conscientious objectors, the women have had no direct role in terminations.

But the pair, who are both in their 50s, claim they should also be entitled to refuse to delegate, supervise and support staff involved in the procedures.

The health board argued that the right of conscientious objection was a right only to refuse to take part in activities that directly brought about the termination of a pregnancy.

In the appeal ruling in favour of the women, Lady Dorrian, with Lords Mackay and McEwan, said: "In our view the right of conscientious objection extends not only to the actual medical or surgical termination but to the whole process of treatment given for that purpose."

The women were employed as labour ward co-ordinators at the Southern General Hospital in Glasgow.

Both registered their conscientious objection to participation in pregnancy terminations years ago, under the Abortion Act, but became concerned when all medical terminations were moved to the labour ward in 2007.

They said being called on to supervise and support staff providing care to women having an abortion would amount to "participation in treatment" and breach their rights.

The appeal will concern the scope of the right to conscientious objection under the Abortion Act 1967 and in particular the decision of the appeal judges that the women's entitlement to conscientious objection includes the entitlement to refuse to supervise staff in the provision of care to patients undergoing termination.