The US Supreme Court has backed a Christian baker who refused to make a wedding cake for a gay couple on the grounds of his religious belief.

Charlie Craig and David Mullins went to the Masterpiece Cakeshop in Lakewood, Colorado, in July 2012, but were told by owner Jack Phillips that he would not provide a cake for a same-sex couple.

The Colorado Civil Rights Commission (CCRC) initially ruled against Phillips but the case was eventually heard by the Supreme Court — the highest court in the US — which overturned the decision by a 7-2 majority in favour of Phillips.

The ruling said the CCRC had violated Phillips' first amendment rights which guarantees freedom of expression.

However the decision focused narrowly on how the case was handled, leaving open the question of whether anti-discrimination laws would supersede religious freedom protections in the future.

Justice Anthony Kennedy, writing for the majority said the CCRC had shown 'hostility' to Phillips' religious beliefs.

'The laws and the constitution can, and in some instances must, protect gay persons and gay couples in the exercise of their civil rights,' Kennedy wrote, 'but religious and philosophical objections to gay marriage are protected views and in some instances protected forms of expression.'

'The court's precedents make clear that the baker, in his capacity as the owner of a business serving the public, might have his right to the free exercise of religion limited by generally applicable laws,' he added.

'Still, the delicate question of when the free exercise of his religion must yield to an otherwise valid exercise of state power needed to be determined in an adjudication in which religious hostility on the part of the state itself would not be a factor in the balance the state sought to reach. That requirement, however, was not met here.'

Ruth Bader Ginsburg and Sonia Sotomayor, the two most liberal leaning judges on the panel, dissented.

Phillips thanks the Supreme Court for the ruling. 'It's hard to believe that the government punished me for operating my business consistent with my beliefs about marriage. That isn't freedom or tolerance,' he said

Phillips was backed by the conservative Christian lobby group, Alliance Defending Freedom and their senior counsel Kristen Waggoner in front of the Supreme Court.

'Jack serves all customers; he simply declines to express messages or celebrate events that violate his deeply held beliefs,' Waggoner said. 'Creative professionals who serve all people should be free to create art consistent with their convictions without the threat of government punishment.'

'Government hostility toward people of faith has no place in our society, yet the state of Colorado was openly antagonistic toward Jack's religious beliefs about marriage,' Waggoner added. 'The court was right to condemn that. Tolerance and respect for good-faith differences of opinion are essential in a society like ours. This decision makes clear that the government must respect Jack's beliefs about marriage.'

Evangelical leaders in America hailed the decision as a major victory. In the presidential election many justified their support of Donald Trump because of his promise to pack the Supreme Court with conservative leaning judges. This case, along with debates about the use of toilets by transgender students, are seen as landmark fights in the so-called culture-wars between traditionalist Christians and those calling for more a liberal approach.

Franklin Graham, son of the famous evangelical Billy Graham, said the decision was a 'huge win for religious freedom'.

Russell Moore, the president of ethics and religious liberty council a the Southern Baptist Convention, tweeted:

He added: