There are growing fears in Northern Ireland that a no-deal Brexit will tip the province into a new era of violence.

Officials there told Business Insider that if the UK leaves the EU without a deal, border controls with the Republic of Ireland would inevitably return.

Any new checks would likely soon become the target of both peaceful civil disobedience and then terrorist attacks.

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NORTHERN IRELAND & LONDON — "I'm starting to hear things that I haven't heard in a long time," Eileen Weir told Business Insider.

"There was a republican funeral here yesterday and they shot over the coffin. I know that's a matter of honour for that fallen comrade, but at the same time, the IRA said all of there guns were out of use, so where did they get that gun?"

Weir runs a cross-community women's centre in Shankill, west Belfast. Shankill was a focus of violence during The Troubles. Irish republican and unionist paramilitaries carried out lethal bomb attacks and shootings on its residents.

"There were five bombs all within half a mile," Weir said, pointing out of her office window.

"I witnessed one when I was 16 or 17 years of age. I was walking down the Shankill and the Four Step Inn [pub] was blown up." Two people died in that particular attack by the provisional Irish Republican Army.

Read more: These business owners on the Irish border fear a no-deal Brexit could soon wreck their livelihoods

Weir received an award for decades of promoting cross-community relations. At the centre — where she first volunteered in the 1990s — women from Catholic and Protestant backgrounds socialise and partake in classes.

When she was 16, Weir briefly joined the Ulster Defence Association, a unionist paramilitary group responsible for over 400 deaths during The Troubles. She sought sugar which was used to create petrol bombs for attacks on Irish Republican targets. Weir quickly abandoned the group to pursue a career in women's issues and equality.

Speaking to Business Insider, Weir expressed a fear that is now widespread across Northern Ireland that violent sectarianism is on the rise again.

"We're seeing it more and more. The guns are back out again," she said.

A mural in Shankill, Belfast. Adam Payne/Business Insider

Brexit could tip Northern Ireland into violence

There have been five attempts to murder police officers in Northern Ireland this calendar year. The most recent was last month, near the border in County Fermanagh, on the day that Business Insider arrived in Belfast.

Dissident republicans apparently used a hoax device to try to lure police officers to a real bomb. Nobody was killed.

Deputy Chief Constable Stephen Martin of the Northern Ireland Police Service (PSNI), warned that Northern Ireland was gradually sliding back towards a level of violence not seen since the 1998 Good Friday Agreement.

"Many of us, and many have reflected to me, that things are becoming more entrenched and progress that has been made is maybe slipping back a bit," Martin said.

More than twenty years on from the signing of Northern Ireland's peace process, the country faces a new crisis.

Politicians, campaigners, and members of the public who Business Insider met in Northern Ireland last week said community tensions were on the rise — and with it a gradual surge in paramilitary activity.

Read more: Northern Ireland feels 'completely ignored' by the UK government on Brexit and it's getting worse under Boris Johnson

Poverty is a big contributing factor. Research published in 2014 found that people living in areas of Northern Ireland where sectarian violence was most rife during The Troubles, have been the biggest losers socioeconomically years on.

Officials believe today there is a direct link between poor life prospects — like unemployment and falling living standards — and dissident republican activity.

However, Brexit and a possible new recession could severely exacerbate this trend. A no-deal exit could put 40,000 jobs in Northern Ireland at risk, Stormont's Department for the Economy said this year.

"I'm only going by what I've seen in the past," Weir told Business Insider. "When there's an economic downturn, and people feel like they're being badly treated in some way, they take their frustration out in other ways."

She added: "The money spent building the Titanic [museum] would have kept good relations council going for 40 years. It's what people I work with see when they leave in the morning, but they can't afford to take their families to it.

"Every church has a food bank now. It was not like that before."

However, the province does not have a government to deal with it — and hasn't since it collapsed in January 2017.

A hard border would become a terrorist target

Where yellow road markings meet white road markings represents the Irish border. Picture taken on Dublin Road. Adam Payne/Business Insider

Officials fear a hard border, resulting from a no-deal Brexit, would quickly become a focus point for dissident republicans who carry out terrorist activity, and that personnel who are subsequently deployed to protect border infrastructure would become human targets.

Boris Johnson has said he will not erect any infrastructure on the border in a no-deal Brexit.

However, the UK government's "Yellowhammer" report into the potential effects of a no-deal Brexit, leaked to The Sunday Times newspaper, suggested that this would not be sustainable. The European Union is preparing to introduce customs and regulatory checks in order to protect the European single market.

However, the threat of increased terrorist activity is not the only concern here.

The Yellowhammer report also warned there would be protests and direct action in Northern Ireland in the event of a no-deal exit.

The concern is that if infrastructure is installed on the border between Northern Ireland and the Republic of Ireland, ordinary members of the public will try to take it down themselves in widespread civil disobedience. This in turn could turn to violence.

"If 60% of people do not want a border on the island, and you say 'tough shit, we are putting you inside a hard border,' you cannot expect people to just choke that down and get on with their lives," Claire Hanna, Member of the Northern Ireland Legislative Assembly for the Social Democratic and Labour Party told Business Insider.

"You cannot imagine that people would take that without civil disobedience at a very minimum."

Brexit will create an identity crisis for people living on the border

Stephen Farry, deputy leader of the Alliance Party, said civil disobedience would be the result of "emotional and psychological impact of checks, which is not grasped by the UK government and in how alternative arrangement people are looking at this."

Farry said the UK government's approach to avoiding a hard border didn't focus enough on the issue of identity, and failed to realised that any change to the status quo — even if away from the border — would create discontent.

He said: "Even if you have checks away from the border, and have them ten miles inland, or you're putting in place mobile patrols and a greater surveillance arrangement, all of that is a border."

"They [UK ministers] think if you avoid lorries stopping for checks, it's mission accomplished, but there are so many more layers. Any notion that you retreating from what people experience today will be seen in a very negative way."

Doire Finn, an activist at pro-EU youth group, Our Future Our Choice, said Brexit "has raised the question of identity," especially among people born after The Troubles, who are asking themselves whether they are British or Irish.

"Before Brexit I found myself feeling identifying as Irish and carrying a British passport because at the time it was easier to apply for. Unfortunately with the threat of Brexit, I and many other people are now applying for an Irish passport so that we are able to have the same rights granted to us as our loved ones."