The appeal by Ashers Bakery against the "gay cake" ruling that saw it prosecuted for refusing to bake a cake with a slogan advocating gay marriage is being heard today.

The case against it was brought by the Northern Ireland Equality Commission on behalf of Gareth Lee, a gay rights activist. He had asked for a cake to be made bearing the slogan 'Support Gay Marriage' for a function marking the International Day Against Homophobia in May 2014. The order was initially accepted but Lee was later told it could not be fulfilled.

Last March District Jude Isobel Brownlie found against the bakers and had discriminated against Lee.

The appeal was due to be heard in February but was dramatically postponed after a late intervention from John Larkin QC, Attorney General in Northern Ireland, which raised a potential conflict between the region's equality legislation (which is not the same as the 2010 Equalities Act) and European human rights laws.

Speaking this morning before the hearing, Daniel McArthur, whose family owns Ashers, argued the case had wide ramifications.

"The Attorney General's involvement confirms there are big issues at stake," he said. "This was never just a case about one little bakery in Belfast. It's always had implications for freedom of expression throughout the UK."

Chief Commissioner of the NI Equality Commission Dr Michael Wardlow said before the hearing: "This is case about a man who walked into a shop two years ago and didn't get the service that he would expect. And I don't want Northern Ireland to be a lottery where when we go into a shop or ask for a service that we have to second-guess the conscience or value base of the service provider."