The battle for same-sex marriage could end up in Europe’s highest courts, lawyer Mark Pettingill said last night.

Mr Pettingill said that Royal Assent for a law designed to replace same-sex marriage with domestic partnerships meant that any further legal action would need to be heard in higher courts.

The former attorney-general, who fought the May 2017 Supreme Court case that paved the way for same-sex marriage, added: “This is now something that would necessarily invite consideration beyond our shores. There is potential for a challenge going all the way to the European courts.”

Mr Pettingill was speaking after John Rankin, the Governor, rubber-stamped the Domestic Partnership Act, which was drawn up to replace same-sex marriage with domestic partnerships for both gay and straight couples.

Mr Pettingill and his team represented Bermudian Winston Godwin and his Canadian fiancé, Greg DeRoche, in their successful landmark case against the Bermuda Government after the Registrar-General refused to publish their marriage banns.

He said: “I take the view, as do a number of other lawyers, that there is a case to be heard on the basis of the rights enshrined in our Constitution.

“The question becomes, are there any relevant parties that are prepared to take up that fight?”

Mr Pettingill added: “I feel that potential is there. Unfortunately, there are the risks of losing, which would probably incur substantial legal costs.

“These things are not cheap to run. Anybody who decided to take up that challenge as a litigant would have to think very carefully about the possibility that they could lose, and the risks involved.”

Mr Pettingill explained that a challenge to the Domestic Partnership Act would represent “a very different case, although of course it related to the same legal issues”.

He said: “It is a fundamentally different position to argue in law. We are dealing with same-sex marriage, with something that became legal on the basis of human rights issues and is now being effectively taken away by an Act of Parliament.”

Mr Pettingill added: “To challenge that clearly is embarking on new legal ground as it relates to the issues and facts associated.

“It presents a far tougher case and a far longer and potentially more drawn-out battle.”

Mr Pettingill said would-be challengers had already approached him to weigh up the merits of further legal action in an international arena.

He added: “We will have to see. I am obviously deeply disappointed, as is a whole segment of right-minded people who feel the same way on human rights issues”.

Mr Pettingill said: “I cannot say I am startled or surprised. It was given full consideration by the Governor. The question now becomes, is there a constitutional legal issue that can bring a challenge in relation to this assent?”

Walton Brown, the Minister of Home Affairs, said the Act represented “a compromise piece of legislation which does not bring any high level of satisfaction to any side” in the island’s long-running row over same-sex marriage.

Mr Brown, speaking from London, added the provisions of the Act were “the only position that could be taken at this point”.

He said: “This difficult piece of legislation was developed in such a way as to ensure that it fully complies with our Constitution.

“Clearly anyone has the right to challenge anything they want, but it must be a challenge with merit.”

Mr Brown questioned the delay between the Act’s backing by Parliament and Mr Rankin’s decision to give it Royal Assent.

He said that the constitutional implications of the Domestic Partnership Act had already been “assessed in great detail” by the Attorney-General’s chambers.

Mr Brown added: “All I will say is that I have never seen any piece of legislation attract this much attention in terms of the timing of the Governor’s signature.

“It has been duly passed by both Houses of Parliament. It passed with a large majority in the House of Assembly, and it was passed by five government and three independent senators, representing the will of the people.”

Mr Brown said: “After this very important piece of legislation, we will move to develop others to help put Bermuda into a better place.”

Mr Godwin said he and his husband were “deeply saddened”.

He added: “It’s a sad day for Bermuda. It’s a sad day for human rights.”

Mr Godwin said: “The Governor was placed between a rock and a hard place with this poorly planned and rushed Bill.”

But he told the island’s LGBTQ people: “While Greg and I were the face of this case, we represented every single one of you and helped to give a voice to those that didn’t have one.

“Because of you, we were able to make a difference in the lives of eight couples and that’s something that shouldn’t be understated or forgotten.

“You are all loved and are worthy of love.”

The Governor’s decision attracted fast condemnation from overseas.

Chris Bryant, the Opposition Labour MP who called for the House of Commons debate, tweeted last night: “So Boris Johnson has granted permission to Bermuda to abolish same-sex marriage. This totally undermines UK efforts to advance LGBT rights.”

Ty Cobb, director at Washington-based Human Rights Campaign Global, called the move a “deplorable action”.

Mr Cobb said: “Governor Rankin and the Bermuda Parliament have shamefully made Bermuda the first territory in the world to repeal marriage equality.

“This decision strips loving same-sex couples of the right to marry and jeopardises Bermuda’s international reputation and economy.

“Despite this deplorable action, the fight for marriage equality in Bermuda will continue until the day when every Bermudian is afforded the right to marry the person they love.”

Sarah Kate Ellis, president and chief executive of New York’s Gay & Lesbian Alliance Against Defamation, added: “LGBTQ couples and their children in Bermuda should know that the global community of LGBTQ people and allies will stand with them in rectifying this unjust and hurtful news.

“Love can never be rolled back.”

Clare O’Connor, a Bermudian journalist living overseas, promised not to send any business towards her homeland.

“I will be encouraging my LGBTQ friends to spend their money elsewhere,” said Ms O’Connor, formerly of Forbes magazine, who has almost 22,000 followers on Twitter.

“This is despicable and I hope the Progressive Labour Party and Governor understand the damage they’ve done.”

Rainbow Alliance Bermuda and OutBermuda did not respond to requests for comment by press time.

Preserve Marriage Bermuda, which campaigned against same-sex marriage, also did not respond to a request for comment.