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The United Kingdom’s Brexit plan appears to have prompted a wave of attacks from the so-called New IRA, a dissident group that never accepted the peace agreement signed by the Provisional Irish Republican Army two decades ago.

The New IRA has claimed responsibility for four letter bombs found in Britain and Scotland this month, sparking concern that the group will step up its attacks if the U.K. re-establishes a border between Northern Ireland and its EU neighbour, the Republic of Ireland.

U.K. lawmakers have been trying to find a long-term solution for the largely invisible divide between the two countries, which would become Britain’s only land border with the EU after Brexit.

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Here’s why the IRA is making headlines again, 20 years after the movement’s leaders signed a peace deal to end decades of bloodshed.

IRA 2.0

The IRA was once the most prominent Catholic paramilitary group in Northern Ireland, a British-ruled, Protestant-majority country north of the Republic of Ireland. The IRA wanted to unite the island as one Irish republic, and its members used assassinations, bombings and kidnappings to protest British rule during an era of violence and hatred on both sides.

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More than 3,700 people were killed in conflicts between Catholic and Protestant paramilitary groups over several decades in Northern Ireland. The violence calmed down after the IRA signed a peace deal with the U.K. in 1998. However, some dissident Republicans refused to give up the fight, and they’ve carried on a low-level militant operation ever since.

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Many of these dissident Republicans call themselves the “Real IRA,” according to Kieran McConaghy, an expert in Irish political violence at St. Andrews University.

“They’re a splinter group that broke away from the Provisional IRA,” McConaghy told Global News. “They’re committed to achieving their goals by the use of violence.”

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Dissident Irish Republicans have staged dozens of attacks using firearms and small bombs over the last 21 years, according to Europol’s 2018 report on terrorism. They’ve also been linked to several forms of crime, such as extortion, fuel laundering and drug dealing.

Their latest efforts appear to be part of a campaign to capitalize on Brexit, McConaghy says.

“When Republicans attack targets in Great Britain, it’s because it gets more international attention than attacking targets in Ireland’s north or south,” he explained. “It puts them on people’s radar.”

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The New IRA likely only consists of a few dozen people, McConaghy says. However, the group could potentially win more support if the U.K. re-establishes a police presence along the border between the two Irelands.

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“They see Brexit and the uncertainty that that creates as a threat but also an opportunity,” McConaghy said. “They can capitalize on that fear and suspicion of the border uncertainty in order to push forward their agenda.”

Brexit, the border and the backstop

The border between Ireland and Northern Ireland has been open and unguarded since the peace deal was signed in 1998. However, it will become the only land border between the U.K. and the EU once Brexit takes effect. Lawmakers have been scrambling to come up with a better solution so a hard border will not have to be imposed.

The prospect of restoring a hard border after Brexit has raised fears of a return to the old days when British army checkpoints, shootings, bombings and gun smuggling were the norm.

Right now, people and goods flow freely from one side to the other, and the border is largely invisible. McConaghy says this free flow is crucial to peace on the island.

“It creates the feeling that they are Irish — that the island is united in some way,” he said.

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McConaghy says a hard border would likely bring British rule back to the forefront of people’s minds in Northern Ireland and make it a rallying point for the New IRA to garner more support.

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“It would upset a lot of nationalists if they were to start to see customs or police checks or military checks along the border again,” he said.

McConaghy says the Northern Irish don’t want to go back to the violent era known as “The Troubles,” although Brexit might help the New IRA recruit new members.

“You might see a bit of a spike, but I don’t think it’s going to be back to the levels that we saw before,” he said. Tweet This

Several residents of Northern Ireland say they worry about a hard border with Ireland.

Seanna Happsley, who commutes across the border from Northern Ireland every day, says Brexit will create a major hassle for her.

“It’s going to be back to the old days,” she told the Associated Press on Tuesday. “Just practical things — school, going to work every day, taking the kids to school and so on — that is going to take a lot of time,” she said.

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Colm Barton, of Londonderry, said he’s worried about peace after the border goes up.

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“No matter what we dress it up as, it will ultimately end with (the) British army protecting British installations in the island of Ireland, and it is absolutely insane,” he said.

—With files from Reuters and the Associated Press