“It’s very, very worrying. Brexit is already impacting Northern Ireland: at the moment, if someone goes south and needs medical treatment, they are covered. But we don’t know if that will remain [when the UK leaves the EU],” says Marie Brown, director of Foyle Women’s Aid in Derry, which supports women and children dealing with domestic violence. “Northern Ireland voted for remain. We didn’t want this.”

Like many others working in public services on the island of Ireland, Brown is angry that in all the debate around the Irish backstop, politicians in Westminster are paying too little attention to the fact that a no-deal Brexit would mean the return of a hard borderthat could put lives as well as livelihoods in danger, for residents on both sides of the border.

For years now, women’s organisations in Northern Ireland and the Irish Republic have worked together to support those affected by abusive relationships, wherever they live. “It can be as simple as crossing a bridge to get help,” says Brown. “If a woman needs to come in [to our services], we can let her in.” Brexit could change all this. In places like Clady, West Tyrone, which is divided from the Irish Republic only by the River Finn, Brown says a hard border could be disastrous. “Women could be stuck, when they could walk over a bridge and get to safety,” says Brown. She worries, too, that a hard border might harm cross-border cooperation between police. “In the days when we had less cooperation, perpetrators used to use the border to avoid being arrested in domestic violence situations. That’s a concern.”

With just over a month until Britain is due to leave the EU, there’s a desperate scramble to tackle the pile of problems that could be caused by a no-deal Brexit. In 2017, a study by the UK government and the European Commission listed 142 cross-border activities on the island that could be negatively impacted by a hard Brexit. It’s not just in domestic violence situations that it could endanger lives. Although police chiefs on both sides have already pledged to continue arrangements that enable them to arrest and extradite criminals, they have warned that it could become harder to share information.

The status of looked-after children from the north could also be a problem. More childen have been placed in foster care in the Irish Republic in recent years, but there are no figures on how many may be affected, says Paddy Kelly, director of the Belfast-based Children’s Law Centre, because the citizenship and immigration status of looked-after children has not been routinely or rigorously recorded. “We’ve been trying to raise these issues ever since 2016,” she says.

Healthcare is a particular concern. In the past few years, all-island agreements have transformed services, with staff, patients, clinicians, medicines and ambulances all free to move between the two countries.

‘Many working in public services on the island of Ireland are frustrated that politicians in Westminster are forgetting that a no-deal Brexit would mean the return of a hard border.’ Photograph: Kirsty Wigglesworth/AP

Some health services have been consolidated, including cross-border cancer and cardiology services at Altnagelvin hospital, in Northern Ireland, and the centralisation of children’s heart surgery in Dublin for the 400 children in the Irish Republic and the 140 in Northern Ireland every year who need heart operations.

Ambulances and fire services attend emergency situations on both sides of the border. Between 2015 and 2018, the Northern Ireland Ambulance Service attended 221 emergency calls in the Irish Republic, while their counterparts responded to 132 incidents in Northern Ireland.

Cross-border arrangements are vital, says Phil Alexander, chief executive of Belfast-based charity Cancer Fund for Children, which supports children and parents across the island of Ireland. He says it’s hard to overstate the importance for families in Northern Ireland of having high-quality medical facilities available in Dublin, less than two hours’ drive away from Belfast – otherwise, people would have to travel to mainland UK for specialist treatment. It makes visiting and supporting ill children far more accessible and less expensive than entire families having to fly over to Bristol, Birmingham or London.

When Janet O’Neill’s son Robbie was just eight months old, he was diagnosed with cancer. A few months later, he was also diagnosed with neurofibromatosis type 1, a genetic disorder than can affect mulitple systems in the body. All-Ireland healthcare means Robbie’s been able to travel wherever he needs for the best-possible care, including brachytherapy (internal) radiation treatment in France and regular checkups at Guy’s hospital in London, as well as visits with his family to the Cancer Fund for Children’s Daisy Lodge facility in Northern Ireland. “There’s so much involved when a child is sick: just getting them the treatment and getting them to the hospital and getting the other child to school,” says O’Neill, who lives in Kilkenny, in the Irish Republic. “Going to Daisy Lodge brought us happiness in all of that. We can just drive up there and the way they looked after us all was indescribable. It was just beautiful.”

O’Neill fears what’s going to happen post-Brexit. While last week’s announcement that the Irish government will continue funding health treatments in Northern Ireland for its citizens after Brexit is welcome, O’Neill, who lives in the Republic, is still concerned. “To have the worry of having a hard border – it takes all the good out of it,” she says. “If there was a hard border, there could be safety issues., “It would put us and other families off going.”

Brexit also risks heightening staffing problems in public services. Every day, almost 15,000 people travel between the two jurisdictions for work or study, according to the risk register compiled by the 10 border councils on the island – five in the north, five in the south – to map out the issues likely to impact their residents, businesses and staff after Brexit. More than a quarter of jobs in Northern Ireland and just under one-fifth in the Irish Republic are in the public sector, and there are a number of practical concerns around how these employees could live and work on both sides of the border.

A Border Communities Against Brexit billboard close to the Letterkenny-Strabane border in the Irish Republic. Photograph: Paul McErlane/The Guardian

Northern Ireland already has a shortage of 2,000 nurses in the NHS and community care sector, and a recent report by the Northern Ireland Council for Voluntary Action (NICVA), which represents 6,000 organisations employing 44,000 people, warns of the dangers of public services becoming a casualty of Brexit. “Freedom of movement and the provision of care and protection on an all-island basis is vital,” it says. And free movement of staffing, medicines and cross-border security, post Brexit is not just for Irish and UK citizens, but for workers from the other 26 EU countries. “Even if there’s a deal, the situation is hardly likely to encourage people to move from the EU26 to Northern Ireland or to encourage Irish citizens to take jobs in Northern Ireland, so that in itself is a factor, when there are already big problems in staffing in health and social care,” says Gordon Marnoch, reader in public policy at Ulster University.

Ultimately, some fear that Brexit could undermine the Good Friday agreement and jeopardise peace, with serious ramifications for public services. In October, the Belfast city region gained £350m from Westminster to develop tourism, infrastructure and digital services. This progress is based on peace and security, says Liam Hannaway, chief executive of Newry, Mourne and Down district council. “I’m not a doomsday person but there is potential for civil unrest,” he says.

Brown says: “When we had violence here, women and children suffered terribly. Are we going to end up going back to those times?”