The Irish will be heading to the polling stations on Friday to vote Yes or No as to whether: ‘Marriage may be contracted in accordance with law by two persons without distinction as to their sex’ should be added to their constitution.

Ireland has a comprehensive constitution which can only be amended by referendum. If the Irish vote yes – and current polling suggests they will – Ireland will become the world’s first nation to legalise same sex marriage through a popular vote.

A yes vote would ratify the Marriage Equality Bill 2015 which was passed with an overwhelming majority by Ireland’s parliament, the Dail, in March. All of Ireland’s political parties are in favour of the change, although some conservative politicians are not.

The most recent polls, undertaken for last Sunday’s papers, show the Yes campaign leading approximately 70 per cent to the No campaign’s 30 per cent, when the ‘don’t knows’ are excluded. However, the result is by no means a done deal, as the Yes vote has slipped by around 10 per cent in recent weeks. Most of that support drifting into the ‘don’t know’ camp, which now numbers around 25 per cent.

There are also concerns amongst yes campaigners over turnout – young people overwhelmingly support the addition of the text, by 70 to 30, but are historically less likely to turn out. Conversely, the majority of those over 65 are No supporters, and are more likely to turn out. As a result, the Yes campaign has focussed in recent days on urging younger voters to ditch the apathy, taking to Facebook to warn: “Don’t be the well-intentioned person in the pub on Saturday night mortified to have contributed to a near miss!” Some 68,000 new voters have been added to the electoral register in the last few weeks.

Nonetheless, their fears are likely to be unfounded as Ireland’s political parties, media and even business interests have all lined up to give their support to a vote in favour of gay marriage. On Wednesday night, Ireland’s Prime Minister Enda Kenny made a plea in favour, saying “There is nothing to fear for voting for love and equality.”

Confronting suggestions that religious schools would be forced to teach their students that gay marriage is equally valid, he said “We have absolute religious freedom here. The churches, irrespective of what church they are, have the absolute right to continue their teaching of their doctrine, their principles and their beliefs. Civil law is a separate matter and there may be questions asked in any school about the civil law.”

Celebrities have also joined the fray. Bono will not be voting but urged others to do so, saying: “You can’t own it. Marriage is now an idea that transcends religion. It is owned by the people. They can decide. It is not a religious institution. As far as I know, Jesus wasn’t a married man and neither are most priests talking about it. It is not a religious idea.”

Hollywood actor Colin Farrell, who has a gay brother who married his partner seven years ago in Vancouver, has also lent the campaign his support. On Monday night Farrell told Irish current affairs presenter Claire Byrne “I try to understand the concerns people have about same sex marriage but I can’t see how a man or a man or a woman and a woman declaring love and faithfulness, and declaring the same things as men and women have for centuries; I can’t see how that could be a threat.”

Ellen DeGeneres, who married her partner Portia De Rossi in 2008 shared the interview with her 38 million Twitter followers, broadcasting his views internationally.

Ireland is still nominally a Catholic country with 85 per cent of the population identifying as Roman Catholic. Last Sunday Catholic priests read out a letter from the Bishops on the matter to their congregations all over Ireland. But the church has kept relatively quiet during the run up to the referendum, as the church, still reeling after a number of scandals, are concerned that openly supporting the No vote could be counter-productive.

Instead the campaign against gay marriage has been left to groups such as Mothers and Fathers Matter, who believe that retaining the definition of marriage as between one man and one woman is in the best interests of children.

They have put up posters urging people to vote “No: Children deserve a mother and a father”.

What is certain is that the referendum has shaken up a sometimes sleepy Ireland. “It’s all anyone’s talking about,” Dublin resident Christine Dilworth told NPR. “I have not had a conversation with a stranger over the last month that has not been about marriage equality.”

Sadly, as with the Scottish referendum on Independence which equally exited the population, events have also taken a darker turn at times. Last week ten year old Muireann DeClár almost lost her life after an event held by the No campaign was attacked with missiles, including eggs.

Muireann, who has a severe allergy to eggs, was sitting on the side of an advertising truck bearing a No poster when she was hit by an egg and suffered a severe reaction. She was only saved by the quick reactions of her mother Aiofe who administered an adrenaline shot. Muireann was taken to hospital, where she made a complete recovery.

Paddy Manning, who had been organising the No campaign event said:

“In all my years of political activism, I have never witnessed such an act of mindlessness, or a scene so distressing. While the attackers had no way of knowing that Muireann had an allergy, they had every way of knowing that she was a child of about ten years old.

“The toxic atmosphere created by the YES campaign is squarely to blame for this incident, of that, there can be no doubt. The event in question was a meet and greet, where no campaigners were trying to engage voters in friendly discussion and polite debate about the decision facing the country in a week. That the response to that engagement from some who disagree with us was to put a child in hospital is absolutely beyond the pale.

“I would like to extend my sympathies, and the sympathies of everybody in the NO campaign to Muireann and her family. They have become the unfortunate victims of a campaign that has lost any and all sense of perspective”.

Polling for the referendum will close at 10pm on Friday night. The final result is expected to be called at around 4 or 5 am, although indications of which way the result is going may come earlier.