DUBLIN (Reuters) - As Britain’s exit from the European Union grows closer with no agreement reached on the Irish border, many in Ireland fear that pro-Brexit British politicians have forgotten the bombs and bullets of three decades of conflict in Northern Ireland and fail to grasp how high the stakes are for the entire island.

FILE PHOTO: A sign for 'No border' is seen on the border between Northern Ireland and Ireland in Jonesborough, Northern Ireland December 10, 2018. REUTERS/Clodagh Kilcoyne/File Photo

London, Dublin and Brussels want to avoid the return of a “hard” border the British-run province and Ireland that existed before a 1998 peace accord brought a tenuous end to “The Troubles” in Northern Ireland - sectarian violence that cost some 3,600 lives, many of them civilians.

The 500 km (350 mile) frontier was marked by British army checkpoints, frequently targeted by IRA gunmen. Belfast and other cities were scarred by riots, shootings and bomb attacks.

British lawmakers who demand an open border but no customs union with the EU sent Prime Minister Theresa May back to Brussels this week to renegotiate the so-called backstop provision in her Brexit agreement – a scenario Brussels rejects as incompatible.

Irish ministers, exasperated that MPs appear blind to the risks, are spelling out how serious they perceive them to be.

“It is vitally important that politicians in Westminster understand the overwhelming wish across society in Northern Ireland not to return to the borders and division of times past,” Irish Foreign Minister Simon Coveney said in a speech.

“Anybody who allows that to happen will be judged harshly by history and rightly so. This government in Dublin is not going to allow it. There are some things that are more important than economic consequences.”

The Ireland question was barely mentioned in the jingoistic campaign mounted by leaders of the drive to pull Britain out of the EU. Since then, comments by some pro-Brexit MPs have not gone unnoticed on the island.

Senior Conservative figure Iain Duncan-Smith dismissed the issue as “this Irish stuff”, while former Brexit Minister Dominic Raab admitted he had not read the 1998 Good Friday Agreement in full.

A prominent BBC journalist even suggested to Ireland’s Europe minister, Helen McEntee, that Ireland quit the EU and join the United Kingdom - an idea met with some bemusement.

Such attitudes only tap into deeper Irish feelings about Britain forged over centuries of colonization and a bloody struggle for independence that left the island partitioned a century ago.

Relations between the two countries improved markedly after the Northern Ireland peace accord, helped along by their mutual membership of the EU.

Police on both sides of the currently open border fear that any checkpoints could be a target for hold-out militant groups opposed to the peace accord. A car bomb outside a courthouse in the Northern Irish city of Londonderry last month underlined that threat and was a stark reminder of the past, although no one was hurt.

John Bruton, Irish prime minister from 1994 to 1997, expressed disappointment at “the lack of sophistication in the British debate” and said an earlier generation of politicians had a much stronger grasp on Irish issues.

“Conservative backbenchers understood fully what was at stake in its relations with Ireland and that allowed Margaret Thatcher to have the (1985) Anglo-Irish Agreement and enabled (former Irish prime minister) Bertie Ahern to negotiate the Good Friday Agreement,” Bruton told Reuters.

“The memories of the atrocities committed by the IRA and loyalist paramilitaries were much fresher in people’s minds 20 or 30 years ago than they are today and Britain, or England, was less self-preoccupied than it is today.”

PANDERING TO THE DUP

The EU insists that the backstop -- a commitment that the United Kingdom would remain bound by EU market and customs rules until the two sides come up with a better idea to avoid checks -- is essential to ensure that, in the words of European Council President Donald Tusk: “We will not gamble with peace.”

However, many in May’s Conservative Party fear the mechanism could keep the United Kingdom tied to EU rules indefinitely.

Bruton said the problem was exacerbated by the lack of any Irish nationalist voice in the British parliament as Sinn Fein, which swept up pro-Republican votes in Northern Ireland in the 2017 election, has a long-standing policy of not taking its seats in Westminster.

That election handed the balance of power to the Democratic Unionist Party (DUP), whose hardline Brexit stance runs contrary to the 56 percent of the Northern Irish electorate who voted to remain in the EU at the 2016 referendum.

As a result, the concerns of the majority have fallen victim to the parliamentary arithmetic of London, the Irish Times newspaper said in an editorial criticizing May’s approach on a visit to Northern Ireland this week.

“The prime minister persists in claiming that she is committed to a solution that commands broad support across the community in Northern Ireland, but she continues to pander to the DUP,” the newspaper said.

“Her claim to speak on behalf of the people of Northern Ireland while rejecting the backstop does not stand up to scrutiny and the EU knows it.”

The message was echoed by Irish Finance Minister Paschal Donohoe, who said his government’s firm position on the border transcended economics even though a no-deal Brexit would damage Ireland’s economy, public finances and jobs.