In 1983, Ailbhe Smyth was spat at and denounced as a “baby murderer” in the street as she campaigned for Irish women to have the right to abortion.

Thirty-five years later, the activist is still at the heart of Ireland’s abortion battle, fighting for her daughter, granddaughter and other women to get control over their bodies.

This time, she is hopeful that the country’s prohibition of abortion, even in cases of rape or fatal foetal abnormality, which is enshrined in the constitution, may be overturned in a referendum expected to be held on 25 May.

The Irish government was expected to confirm the date and wording of the referendum on the eighth amendment – the clause in the constitution that gives foetuses and women equal right to life – on Tuesday, but the move has been delayed by a forthcoming Supreme Court judgement that has repercussions for the rights of an unborn child.

If the vote is in favour of repeal, the government is expected to introduce legislation permitting unrestricted abortion during the first 12 weeks of pregnancy.

Smyth, who leads the Coalition to Repeal the Eighth Amendment, said: “We are absolutely determined to win this campaign, but we have learned that you should never try to second-guess the people in a referendum.

“We know that a majority of people want change. Ireland is a different country today, a more equal society. This is the logical next step.”

About 3,500 Irish women travel to the UK each year to terminate their pregnancies, incurring large costs, facing logistical difficulties and undergoing emotional strain.

Another estimated 2,000 women a year end pregnancies by taking the abortion pill, illegally obtained online, without medical supervision.

“We need to be honest with ourselves. The reality is that abortion does happen, but we can’t go on exporting it,” said Smyth. The present situation adds “layers of psychological stress” to women who need to end pregnancies, she said.

The eighth amendment was inserted into the constitution under pressure from the Catholic church, according to Smyth. “There was no abortion in Ireland. There was already a stringent law against it. It was a crime punishable by life imprisonment,” she said.

“But rightwing forces, rooted in the Catholic church, moved to enshrine it in the constitution, to copper-fasten it. They said ‘If we don’t act, abortion will become rampant’, that abortion is evil, a mortal sin. They used very violent language.”

The amendment was intended to make the issue of abortion untouchable. “The constitution should be the place for the values and aspirations of a society, not a place where you deal with the complexities and messiness of everyday life. That’s a matter for legislation,” Smyth said.

In 1983, the former academic and other activists held rallies, marched and canvassed door to door. “It was a very bitter and divisive campaign. I was spat at many times,” Smyth said.

Although one in three voters rejected constitutional change, the amendment was backed by a large majority.

But there have been significant social and demographic changes in Irish society over the past 35 years. The influence of the church has waned after sexual abuse scandals and cover-ups in the 1990s. Although 78% of the population identified as Catholic in 2016, the proportion is significantly smaller among under-35s. Between 1972 and 2011, weekly church attendance fell from 91% to 30%. In Dublin, it dropped to 14%.

Immigration has produced a more diverse society and people who left Ireland to find work elsewhere have returned, often with a more liberal outlook. The internet and social media have challenged the authority of the pulpit.

Three years ago, Ireland became the first country in the world to back same-sex marriage in a referendum, against the church’s exhortations. The vote had an empowering effect; people realised they could force change.

In January, a poll found 56% would vote in favour of repealing the eighth amendment and allowing unrestricted abortion up to the 12th week of pregnancy, with 29% against and 15% undecided or unwilling to say. Among those aged 18 to 24, support for change was at 74%, compared with 36% among over-65s.

According to Smyth, many of those yet to make up their mind “feel a real moral dilemma about the legislation that will follow repeal. You have to remember that almost everyone voting in this referendum has been through an education system run by the church, which has taught that abortion is murder”.

“It’s very important to listen to their fears and to explain that women need to be able to access early, safe abortions without restriction,” she said.

Smyth said she and other repeal campaigners have “a huge ground campaign planned, and we’ll be using all the social media tools at our disposal” in the coming weeks.

Volunteers are being trained to canvass people door to door. Rallies and street stalls will give the repeal campaign a high degree of visibility. Attention will be focused on undecided voters in small towns.

“I have fought on this issue for all my adult life,” said Smyth, who will turn 72 a few days after the vote. “And I will go on fighting just as long as I have a voice.

“If we don’t have the capacity and right to make decisions about our own lives as women, we don’t have equality.

“And if by some great misfortune we don’t win this battle, we’ll be back on the streets. Maybe not the very next day, but the day after. We will not stop now.”