The legalisation of civil unions has brought a wave of euphoria to California, dancing on the streets of San Francisco — and the prospect of more than half a billion dollars to the economy.

Arnold Schwarzenegger, the Governor of California, has said that he hopes the state's legalisation of same-sex unions will provide a much-needed cash injection as couples from all over America travel to the West Coast for lavish ceremonies.

Among the first gay celebrities to take advantage of the new law in the Golden State will be the talk-show host Ellen DeGeneres, who immediately announced plans for a civil partnership with her long-time girlfriend, Portia de Rossi, after the ruling by the California Supreme Court last month. The actor George Takei, who played Mr Sulu in Star Trek, also plans a civil partnership with his same-sex partner in California.

The Supreme Court ruled on May 15 that all couples have a “basic civil right” to marry “without regard to their sexual orientation”. The law will come into effect on June 17, and California's 58 county clerks have already received the new-style marriage licences that say “Party A” and “Party B” instead of bride and groom.

According to a report from the Williams Institute on Sexual Orientation Law and Public Policy at the UCLA School of Law, same-sex couples could spend as much as $692million (£350million) on wedding ceremonies in California over the next three years.

Governor Schwarzenegger, a liberal Republican, has wished gay couples well in spite of his longstanding opposition to the legalisation of same-sex marriages. “I'm wishing everyone good luck with their marriages, and I hope that California's economy is booming because everyone is going to come here and get married,” he said.

The issue of gay marriage is likely to remain a controversial topic during the general election, but a Field Institute poll last month showed that 52 per cent of Californians supported civil partnerships, compared with 41 per cent against.

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