The teenager fought her legal battle in the High Court in Dublin

The 17-year old was told by doctors her four-month foetus would not live more than a few days beyond its birth.

She is in the care of the Irish Republic's health service, which had issued an order stopping her from going to Britain.

Abortion is illegal in the Republic except when the mother is threatened by a medical condition or a suicide risk.

Thousands of Irish women get around the ban by privately travelling to Britain, where abortion was legalised in 1967, to undergo terminations.

The Irish Republic has a constitutional ban on abortion, but in 1992 made it legal to receive information about foreign abortion services and to travel for abortions in Britain.

An estimated 7,000 women travel outside Ireland each year to terminate unwanted pregnancies.

The High Court has now ruled there were no statutory or constitutional grounds for preventing the teenager, known only as Miss D in court, from travelling to Britain for the operation.

Legal arguments

Justice Liam McKechnie had heard arguments over the past week from three sides.

These were the girl and her estranged mother, who both approve of the abortion; her legal guardians at the Health Service Executive (HSE) - the republic's national health service, which opposed the abortion at first but has since altered its position; and lawyers appointed by Attorney General Rory Brady to represent the right to life of the foetus.

The teenager comes from the Leinster region and has been under the guardianship of the HSE since March.

Doctors said Miss D's foetus has anencephaly, a condition which means that a large part of the brain and skull is missing.

Babies with anencephaly live a maximum of just three days after birth.