Fine Gael are considering holding a referendum on same-sex marriage next year, but not promoting a Yes vote, in order to avoid a damaging split, it has been reported.

The Cabinet is to ask the Attorney General whether it is possible to hold referenda without the Government taking a formal position on them, according to the Sunday Times.

The Government is planning to hold referenda on issues which were discussed by the Constitutional Convention, including the issue of same-sex marriage.

However, having placed maximum pressure on his TDs to back his controversial abortion bill, Taoiseach Enda Kenny is reported to be eager to avoid another row over a sensitive social issue.

One Fine Gael source acknowledged that Mr Kenny had “lost a lot of political capital with the parliamentary party” on the abortion issue and that there would be “very little tolerance among a lot of Fine Gael TDs if they were forced to support any more divisive social issues”.

“We lost five people over abortion and there’s a sombre, angry mood in the party. If we had to support gay marriage it would push a lot of people over the edge.”

The Tánaiste, Eamon Gilmore, has said he would like a referendum on same-sex marriage next year, but Mr Kenny has repeatedly refused to give any indication of his stance on the issue.

Constitutional expert Professor Gerry Whyte said that there was no legal impediment to the Government putting a referendum to the public without supporting it.

Professor Whyte cited the 1983 abortion referendum, which passed a vote of the Oireachtas and was put to the people despite the fact that then Fine Gael Government opposed it.

“It would seem to follow, then, that the Government may remain neutral on, or even opposed to, any proposal put to the people to amend the Constitution,” he said.

Meanwhile, the UK is set to become the latest country to legalise same-sex marriage after it passed the House of Lords yesterday.

The Bill is now expected to be presented to the Queen for her signature. But opponents of the Bill said that the Government had used “bulldozer” tactics ram the Bill through the Houses of Parliament, the Daily Telegraph reports.

Conservative peer Lord Framlingham said it was be a “deeply sad day” for people who believed in the “traditional family”.

Meanwhile the Coalition for Marriage (C4M), the group which orchestrated opposition to the Bill, is planning to campaign during the 2015 election.

It says it has built up a database of around 700,000 supporters through its petition against the redefinition of marriage and its leaders say they have enough support to influence the outcome of the next election.

They have compiled a list of 39 of the most marginal seats they plan to target and in which enough people signed the C4M petition to suggest they could swing the election result.

They plan to challenge candidates of all parties to back a list of commitments to introduce new legal protections for workers such as teachers and registrars who hold to a traditional line on marriage.

They will also be campaigning to open up civil partnerships to allow family carers and unmarried siblings to benefit from the same inheritance tax exemptions as married couples.

Colin Hart, campaign director of the C4M said: “Mr Cameron needs to remember that the Coalition for Marriage has nearly 700,000 supporters, nearly six times the number of members of the Conservative Party.

“They are just ordinary men and women, not part of the ruling elite. They are passionate, motivated and determined to fight on against a law that renders terms like husband and wife meaningless and threatens one of the foundations of the institution of marriage: fidelity and faithfulness.

“These concepts may not matter to the leaders of the three main political parties, who are drawn from a very narrow liberal political class, but they do matter to people up and down the country who believe that marriage is special, unique and the bedrock of stable families.”

Meanwhile, Lord Cormack, the former Tory MP, who opposed the bill, said it would be “churlish” not to accept that the supporters had won.

He said: “I want to congratulate all those who have campaigned for this measure upon their success.

“But in doing that I would just ask them to bear in mind that although this may be a day of unqualified rejoicing for them, there are many in our country who by no stretch of the imagination could be called either homophobic or bigoted who are unhappy about this Bill.

“They are unhappy about this Bill because it does change the structure of society by changing the definition of marriage.”