ASHLEY HALL: Despite some hefty opposition, the British government's bill to make gay marriage legal in England and Wales is on its way to becoming law.

The Scottish government is expected to introduce a similar bill to its parliament by the end of the month.

That's left gay groups in Northern Ireland concerned that they could soon be in the only part of the United Kingdom where same-sex marriage is not permitted.

Europe correspondent Barbara Miller reports.

(Sounds from a bar)

BARBARA MILLER: These days there's a thriving gay scene in Northern Ireland's capital, Belfast.

JOHN O'DOHERTY: There's never been a better time to be lesbian, gay, bisexual or trans-gender in Northern Ireland.

BARBARA MILLER: John O'Doherty is chairman of the lobby group Equal Marriage Northern Ireland.

JOHN O'DOHERTY: There was a huge invisibility of our community for the decades that we had troubles here in Northern Ireland. It was very hard to get people to focus on inequalities experienced broadly within communities because it was such a huge conflict here and it was impacting on people's everyday lives.

BARBARA MILLER: In 2005 Northern Ireland witnessed the first same-sex civil partnership in the United Kingdom.

LESBIAN COUPLE: We just want to say that this is a very privileged position we're in this morning to have our rights, our civil rights acknowledged and respected and protected as any human being.

BARBARA MILLER: But the country could become the last place in the UK where gay marriage is legalized.

Northern Ireland's largest political party, the Democratic Unionist Party, is strongly opposed.

Brian Kingston is a DUP councillor in Belfast.

BRIAN KINGSTON: We do not support the redefinition of marriage. We think that marriage is a - not just for centuries, for millennia - has existed and has been a valued part of society. Marriage should be between one man and one woman of a certain age and that this is the only two people in marriage and that they're one man and one woman and we don't support the redefinition. Just because people want something to change doesn't make it a good idea.

BARBARA MILLER: The DUP says there's widespread support for its stance.

John O'Doherty again.

JOHN O'DOHERTY: I disagree. I don't think there's any basis to make that assertion.

(Sound from the street)

RESIDENT: Yeah, I'm all for it. Each to their own. You know what I mean? Let them do it.

RESIDENT 2: I certainly wouldn't have any objection to it. It seems a perfectly reasonable desire on the part of the gay community to me so.

RESIDENT 3: I would have some friends who would be gay but I think that's taking it a step too far. I don't mind the civil partnerships but I think marriage should be very much between a man and a woman.

RESIDENT 4: I just think it goes against natural evolution.

BARBARA MILLER: So the government says that a majority of people are opposed. Is that your feeling, that your opinion is widely held?

RESIDENT 4: I think it's is widely held but I also think that a lot of people wouldn't express it through fear of being labelled as being discriminatory in some way.

BARBARA MILLER: Amnesty International is supporting the call from rights' groups for gay marriage to be made legal.

Patrick Corrigan is the organization's Northern Ireland program director.

PATRICK CORRIGAN: I think there's a significant and growing support for equal marriage rights in Northern Ireland, just as there is in across western Europe and many other countries now.

And we're seeing a trickle turn into a stream, turn into a river and into a torrent of equality rushing across the world and I think it will wash up on Northern Ireland's shores sooner or later whether politicians like it or not or whether indeed some religious institutions like it or not.

And if they're unwilling to act then I think in the case of equality that is when the courts have a legitimate role to play. If legislators are not willing to legislate for equality then the judges may well have to intervene if they're asked to do so by the citizenry.

BARBARA MILLER: In the early 1980s a gay activist took his fight to the European Court of Human Rights for Northern Ireland to follow the rest of the UK and decriminalize homosexual acts.

He won the case, much to the displeasure of the Reverend Ian Paisley and his Save Ulster from Sodomy campaign.

IAN PAISLEY (Archival): You will legislate perversion and immorality.

BARBARA MILLER: If Northern Ireland's politicians or courts won't back the call for same-sex marriage, activists say they'll also be taking this issue to Strasbourg.

This is Barbara Miller in Belfast reporting for PM.