Gay rights campaigners take part in a march through Belfast on July 1, 2017 to protest against the ban on same-sex marriage. (PAUL FAITH/AFP/Getty Images)

Northern Ireland may be another step closer to legalising equal marriage as a bill undergoes its second reading in Parliament on Friday.

Northern Ireland is currently the only part of the UK that continues to ban same-sex marriage, due to opposition from the ultra-conservative Democratic Unionist Party.

However, a bill legalising same-sex marriage, proposed by Northern Ireland-born Labour MP Conor McGinn, was introduced to Parliament on March 28.

The proposed equal marriage legislation will enter its second reading in the House of Commons on May 11, where it is expected to be more intensely debated.

A twin of the bill is currently moving through the House of Lords, potentially shortening the time required to pass the legislation if both pass.

In a letter to the Secretary of State for Northern Ireland, Karen Bradley, McGinn called on the Government to “get off the fence and do the right thing” by supporting the legislation.

The MP told the Belfast Telegraph: “In Westminster, there is cross-party support in both the Commons and the Lords for equal marriage in Northern Ireland and the Secretary of State has confirmed that the Government will quite rightly treat this as it would any other issue of conscience – with a free vote.”

“In order for my Bill to proceed and bring equal marriage in Northern Ireland another step closer, we need the Government to allow its passage at its Second Reading on Friday.”

He continued: “I’m calling on the Government to get off the fence and do the right thing by the people of Northern Ireland and the thousands of same sex couples who are denied their right to marry by allowing this Bill to proceed.”

There is multi-party support for the proposal, with MPs from a variety of political parties supporting the measure.

Two former Equalities ministers, Nicky Morgan and Justine Greening, have both given their support for the bill.

Related: Why doesn’t Northern Ireland have equal marriage yet?

Following the collapse of Northern Ireland’s devolved power-sharing government, campaigners in the region have said that responsibility for bringing about equal marriage now lies with the UK Parliament.

However, UK Prime Minister Theresa May recently said the issue should wait until the Northern Ireland Assembly is restored, but this legislation could bring about equality sooner.

During the first reading of the current bill, Prime Minister Theresa May stressed that she would rather the issue was dealt with by the Northern Ireland Assembly.

A previous attempt at bringing marriage equality to Northern Ireland in 2015 failed after the ultra-conservative Democratic Unionist Party overturned the Assembly’s decision.

The 2015 bill narrowly passed through the devolved assembly with 53 votes in favour and 51 against, winning a majority for the first time.

In most places that would have been that – the bill got a majority of votes, so it would become law.

However, using a peace process power known as a ‘petition of concern’, the DUP were able to file a petition to block the bill.

Northern Ireland Secretary of State Karen Bradley has also said that while same-sex marriage should be debated in the devolved Northern Irish assembly, the Government will allow a free vote on the bill as a “matter of conscience”.

Support for marriage equality in Northern Ireland has risen singificantly since the attempted bill in 2015.

A poll conducted in April showed that 76 percent of people in Northern Ireland think same-sex marriage should be legal, with just 18 percent – less than one in five – opposed.

The poll demonstrates a surge in support on the issue, climbing from 68 percent support in 2015.