The California Supreme Court has upheld Proposition 8, the initiative which banned gay marriage in the state.

In the 6-1 decision, the judges rejected an argument from gay marriage supporters that the ban was unconstitutional but unanimously ruled that the 18,000 gay couples who married while gay marriage was legal will stay wed.

The only judge who wanted Prop 8 to be struck down was Justice Carlos R. Moreno, who was the court’s sole Democrat.

Gay activists had said that the ban revised the California constitution’s equal protection clause to the point of needing Legislative approval.

The ruling said: “In a sense, petitioners’ and the attorney general’s complaint is that it is just too easy to amend the California constitution through the initiative process. But it is not a proper function of this court to curtail that process; we are constitutionally bound to uphold it.”

The crowd of gay marriage supporters who watched the hearing live on screens outside the San Francisco courthouse chanted “Shame on you” as the decision was announced.

Gay marriage was legalised in California in May 2008. However, Prop 8 defined marriage as being between a man and a woman last November. Supporters of gay marriage argued the initiative was unconstitutional and discriminatory.

The Supreme Court examined whether a voting majority can overrule minority rights previously recognised by the court, as it had previously declared that gays and lesbians have a constitutional right to marry.

Gay marriage advocates are expected to hold protests today against the ruling.

California allows gay couples to have civil partnerships but activists say these are not equal to marriage.

The following video report is brought to you by local news service KCRA3.