LONDON — In Ireland, we say the past is never over. And it has come back to haunt us as the prospect of a disorderly Brexit looms.

I was 9 years old when the war we euphemistically call “the Troubles” began in Northern Ireland.

“Troubles” doesn’t come close to describing it.

I vividly recall the bloodstained images of the attack on civil rights marchers by police in 1968 that set off this terrible explosion of violence. It was a war that not only killed more than 3,700, it injured an estimated 47,000 people in at least 37,000 shootings and over 16,000 bombings.

Northern Ireland is a small place, around the size of Connecticut, where everyone, it’s said, knows everyone. The equivalent death toll per head of population in the United States would be around 750,000 people.

For those of us who were children when the Troubles began, who lived through its daily carnage and who believe lives are at stake in the Brexit drama, these are distressing times.

The three-year trauma is threatening to re-establish a so-called hard border between Northern Ireland, which is set to leave the European Union, and the Republic of Ireland, which will remain a member.

For more than 20 years there has been a fragile peace in Northern Ireland, based on the Good Friday Agreement of 1998, which ended the conflict. But it’s also an international agreement the British government is threatening to break in its haste to tear itself away from the E.U., with or without a deal.

Communal trauma

The Troubles were a communal trauma. My generation lived through it. Like most people, I knew many victims.

Liam Canning, 19, whom I played football with, was murdered by gunmen. Fourteen-year-old Rory Gormley, who was in my year at school, was shot and killed by militants who tried to murder his father.

Five members of a soccer club I played for were murdered. At another club I played for — a mixed team of Protestants and Catholics that dominated junior soccer for years — the toll was similar; one member was the IRA hunger striker Bobby Sands, who starved himself to death in 1981.

I heard shootings and bombings every week at my school in Central Belfast, close to an area known as “murder mile.”

I wore a school uniform whose colors we could strip off so that no-one could identify our religion and target us. My mother’s business in central Belfast was damaged by bomb attacks. In our late teens, my friends and I shunned pubs because of the danger of bombings; one of my friends had his legs blown off in one.

While I was in college, a prominent lawyer was murdered outside my building. As a young journalist I covered dozens of murders. I was warned by police of a credible death threat against me and several other reporters, and for months afterward I checked under my car for bombs and varied my route home.

So it’s personal, as it is for everyone in Northern Ireland watching the Brexit chaos and fearing the divorce may tear to shreds an imperfect but effective peace. Some may call it an exaggerated fear, but if you’ve lived through a war, you don’t forget the horrors easily.

A couple walks past a mural of Bobby Sands in the Falls Road on April 10, 2008, in Belfast. Peter Macdiarmid / Getty Images file

Many of those who support Brexit appear certain these fears are overblown.

They reassure voters that the issue of the Irish border may be a thorny problem, but is not the trigger for renewed violence. British leaders promised repeatedly that there would never be a hard border of manned customs checkpoints across 310 miles, which could become the target for militants bent on erasing them.

But British Prime Minister Boris Johnson now says there will have to be a series of customs checks, away from the border.

It’s unclear how those checks would operate. There isn’t a frontier in the world where technology replaces checks, where barcodes replace a border. And Northern Ireland has 208 border crossings, an invisible line between the U.K. and the Republic of Ireland that runs along the middle of 11 roads, meets in the middle of three bridges and dissects two ferry crossings.

Astonishingly, there are more crossings in Ireland than along the entire border between the U.S. and Canada, and between the European Union and the countries to the east, where there are 137 crossings. During the Troubles, most of the Irish border roads were blown up or blocked with spikes.

Watchtowers, manned by British soldiers, loomed over the border, creating the feel of an open prison. Border residents often waited hours for security clearance to pass a border that today they can cross unhindered several times a day.

British Army Observation Post on the roof of a council tower block overlooking the republican New Lodge area of Belfast, Feb. 20, 1978. Alex Bowie / Getty Images file

There are no customs checks between two countries inside the E.U., and the vague and untested British proposals for an invisible border after Brexit have been consistently rejected by the E.U.

Brexit supporters insist all this can be easily solved.

One major hurdle to any agreement is that many in the Republic of Ireland and Northern Ireland simply don’t trust the current leadership in the U.K., especially Johnson, who has a proven history of dishonesty.

They don’t believe recent British governments have understood the historical hornet’s nest they are stirring. Brexit conjures up old fears in Ireland of an English ruling class that will happily sacrifice the Irish on the altar of its own nationalist ambitions.

Take the prime minister who once compared the Irish border to the boundaries between two London boroughs, Camden and Westminster. He insisted that the border was not a complicated issue.

“It’s so small and there were so few firms that actually use that border regularly, it’s just beyond belief that we are allowing the tail to wag the dog,” Johnson said. “We are allowing the whole of our agenda to be dictated by this folly.”

Yet in office he has never visited the border of a province he governs.

One of Johnson’s first acts as prime minister was to renege on a commitment Britain made in December 2017 to keep Northern Ireland aligned with E.U. customs rules. When he was foreign secretary he asked why Irish Prime Minister Leo Varadkar “isn’t called Murphy, like all the rest of them.”

Johnson’s colleague in Brexit fundamentalism, lawmaker Jacob Rees-Mogg, has insisted he had no reason to go to the Irish border to inform his views.

“I don’t think my visiting the border is really going to give me a fundamental insight into the border beyond what one can get by studying it,” Rees-Mogg said.

Boys mill around a car they have just set on fire in Belfast in 1988. David Turnley / Corbis/VCG via Getty Images file

When Brexit Party leader Nigel Farage was asked if he had ever considered Northern Ireland during the referendum campaign in 2016, he admitted never giving it a moment‘s thought.

“No, no, no, what’s the problem? There is no problem,” he said.

These comments stir up old resentments among many in Ireland who believe there is a deep ignorance of the island’s history among English lawmakers and its elite.

As prime minister, Margaret Thatcher wanted the border redrawn with a straight line because it would be “easier to defend” than the real one with “all those kinks and wiggles in it,” according to her private secretary, Sir Charles Powell.

Nigel Lawson, Thatcher’s former chancellor who chaired the campaign to leave the E.U., suggested before the 2016 referendum that he’d be happy if the Republic of Ireland said it had “made a mistake in getting independence in 1922” and came back in the United Kingdom.

When in trouble, blame the Irish

Brexit supporters today deeply resent what they see as the stubbornness of the Irish leadership, backed by bureaucrats in Brussels, in not agreeing to their demands. The Johnson government has begun a campaign of blaming Dublin, Berlin, Brussels and Paris for its own inability to achieve a parliamentary solution to the Brexit crisis that Britain created.

When in trouble, blame the Irish.

Or, in that old and condescending English joke, whenever the Irish question was about to be solved, the Irish changed the question. In their desperation to leave the E.U., 59 percent of ruling Conservative Party members said they wanted Brexit to happen even if it meant breaking up the U.K., with Northern Ireland leaving and joining a united Ireland.

Today’s Irish government sees its British counterparts, or at least the English nationalists behind them, as ignoring an inconvenient truth. And that is that the whole of the U.K. cannot leave the E.U.’s customs union without the return of a hard border in Ireland.

Jonathan Powell, Britain’s chief negotiator in Northern Ireland from 1997 to 2007, wrote recently, “Be under no misapprehension, there will have to be checks and there will be a hard border, which will undermine the basis on which the Good Friday Agreement was built.”

Which takes us back to the real unease at the possibility of a return to violence.

The British government is so worried about the resurgence of conflict in Northern Ireland that it has set the terror threat level at severe. The MI5 British security service now has more than 700 officers operating there. Hundreds of police officers from England and Scotland have been trained in anti-terror tactics in case they are needed for fast deployment.

The Republic of Ireland has just established a new armed police support unit along the border to prepare for Brexit.

There are indications that violence could be on its way back, and police in Northern Ireland have recently found bombs.

One was designed to lure police officers into an ambush. Another was found attached to a policeman’s car.

Journalist and author Lyra McKee Jess Lowe Photography / AFP - Getty Images file

Two terror groups operate in Northern Ireland; one was responsible for the murder of a journalist, Lyra McKee, in April. Neither has much support, but violence, once unleashed, is a beast that’s hard to restrain. And it thrives in a political vacuum, which is what the region has today.

After a political battle unrelated to Brexit, Northern Ireland’s regional government collapsed. It is more than 1,000 days since its politicians sat in their Parliament. Work on health, education, housing and industry has stalled. Many people are resentful and feel abandoned, a potential pool of the discontented ripe for recruitment by unscrupulous extremists.

From Ireland to Iraq, terrorism has fed off the oxygen of grievance. And Brexit is feeding frustrations. One woman from the border town of Crossmaglen, a cockpit of violence during the Troubles, told me, “If the British impose a hard border here, let there be another war.”

Sinn Fein, which for decades defended the bombing and shooting campaign of the Irish Republican Army, says it “will not tolerate anything that resembles a border. The British government has been shown to be lying; what Boris Johnson is proposing is a significant hardening of the border.”

Sinn Fein leader Gerry Adams (fourth from left) and Sinn Fein deputy leader and alleged IRA chief of staff, Martin McGuinness (third from left) attend the funeral of an IRA volunteer in Buncrana, County Donegal, Ireland, Sept. 20, 1985. Kaveh Kazemi / Getty Images file

The feelings of injustice and resentment spring from hard fact.

In the 2016 Brexit referendum, 55.8 percent of the Northern Ireland electorate voted to remain in the E.U. But the overall U.K. vote, 52 percent to 48 percent, means that Northern Ireland will be exiting the E.U.against its will.

Its people are now divided about their future; in December 2017 a poll found that faced with a hard Brexit, 48 percent of Northern Ireland voters would opt to leave the U.K. and join a united Ireland, while 45 percent would rather stay in an exiting U.K. The proportion of those who prefer a united Ireland has since increased.

The ghosts of identity are being stirred again in a once deeply troubled land, ghosts laid to rest by the Good Friday Agreement, an international treaty signed by two sovereign nations. It was a deal built on a creative ambiguity; that residents north and south of the border could identify as British or Irish or European or any combination of the three, regardless of where they lived and what their religion or politics might be.

That delicate balance may soon be kicked to death by the binary brutality of Brexit.

Before her death at the hands of a militant gunman in Londonderry this year, Lyra McKee wrote: “We were the Good Friday Agreement generation, destined never to witness the horrors of war but to reap the spoils of peace. The spoils just never seemed to reach us.”

Now peace itself, not just its spoils, is threatened in Ireland.

And for those of us who lived through the terrible destruction of peace over three brutal decades, it’s a worrying prospect, and one that should horrify every lawmaker in Britain.