The court says the ban on abortion in the case of rape, incest or fatal foetal abnormality is incompatible with the European Convention on Human Rights.
The ruling means the legislation will have to be altered – either by a re-reading of the existing law – or by the Northern Ireland Assembly.
The decision could have knock-on effects in the Republic.
The abortion law in Britain does not extend to Northern Ireland, where abortions are banned unless the life or mental health of the mother is in danger.
Today's landmark decision stems from a challenge to the North's abortion legislation by the Northern Ireland Human Rights Commission.
Judge Mark Horner found in favour of the NIHRC, and ruled that the abortion legislation breached the rights of women under article 8 of the European Convention on Human Rights.
The Judge said that the issue was unlikely to be grasped by the legislature in the foreseeable future, and proposed two options.
The case is back before the High Court on December 16th, and Judge Horner has asked the parties to make submissions on whether its possible to read the law in such a way to ensure that no offence is committed by terminating pregnancies involving a fatal foetal abnormality or a sexual crime.
Bernie Smyth from Precious Life says they'll be making their own submissions. Ireland's legislation on abortion was previously found to be in breach of Article 8, but this was seen to have been addressed by the Protection of Life during Pregnancy Act introduced last year.
However with the debate on repealing the 8th back in on the political agenda, it's an issue that shows no sign of going away.
