The Christian Institute has said that the owners of Ashers Baking Company are to appeal a Belfast court ruling that the bakery discriminated against a customer by refusing to make a cake with a slogan supporting same-sex marriage.

The Northern Ireland Equality Commission brought the case against Christian-owned Ashers Baking Company on behalf of Gareth Lee, a gay rights activist whose order was declined.

Giving her ruling at Belfast County Court earlier this month, district judge Isobel Brownlie said: "The defendants have unlawfully discriminated against the plaintiff on grounds of sexual discrimination.

"This is direct discrimination for which there can be no justification."

Ashers was ordered to pay agreed damages of £500 (€690) plus court costs. Mr Lee, a member of the LGBT advocacy group Queer Space, had wanted a cake featuring Sesame Street puppets Bert and Ernie with the slogan Support Gay Marriage.

He wanted the cake for a private function marking International Day Against Homophobia.

In a statement today the McArthur family, who own and run Ashers, said: "After much careful and prayerful consideration given to legal advice, we have decided to appeal the judgment handed down last Tuesday."

The statement added: "We continue to insist that we have done nothing wrong as we have discriminated against no individual but rather acted according to what the Bible teaches regarding marriage.

"As many other people have already noted, Christian beliefs seem to have been trampled over in this judgement and we believe this only has negative effects for our society.

"Our hope and prayer would be that an appeal will allow us and other Christians to live out their faith in Jesus Christ in every part of their lives, including their workplace."