The European Court of Human Rights (ECHR) has dismissed a case against a Christian baking company that refused to bake a cake with a pro-gay marriage slogan.

Gay rights activist Gareth Lee wanted Ashers Baking Co in Belfast to bake a cake iced with the words 'Support gay marriage'. When bakery owners Colin and Karen McArthur declined the order, he sued them in 2014.

Four years later, the UK Supreme Court ruled that they were within their rights to turn down the order.

In their ruling, five Supreme Court judges determined that the issue was being required to promote the message on the cake and not Mr Lee's sexuality, and that equality law does not compel people to say something they profoundly disagree with.

Following the Supreme Court win for the McArthurs, Mr Lee brought a case against the UK Government to the ECHR in Strasbourg. 

His lawyers attempted to argue that the European Convention imposes a positive obligation on the UK Supreme Court to ensure that Ashers Baking Co and the McArthurs personally are required to provide him with a product that carries a political message they disagree with.

Although the McArthurs and The Christian Institute, which has supported the family since 2014, were not parties in the ECHR case, they both made written interventions through their lawyers arguing that the appeal should be dismissed.

Simon Calvert, spokesman for The Christian Institute, said the ECHR's decision to dismiss the appeal was "the right result".

"The UK Supreme Court engaged at length with the human rights arguments in this case and upheld the McArthur's rights to freedom of expression and religion. It was disappointing to see another attempt to undermine those rights, so it is a relief that the attempt has failed," he said.

"I'm surprised anyone would want to overturn a ruling that protects gay business owners from being forced to promote views they don't share, just as much as it protects Christian business owners.

"The ruling in October 2018 by five of the country's most distinguished and experienced judges was welcomed by lawyers, commentators and free speech experts from across the spectrum.

"They all knew of the implications for freedom of speech and religion, had the decision gone against Ashers. This could have included a Muslim printer being forced to print cartoons of Muhammad, or a lesbian-owned bakery being forced to make a cake describing gay marriage as an 'abomination'.

"This is good news for free speech, good news for Christians, and good news for the McArthurs."