FIONA Strain would walk home from school and see them in the bushes.

Armed soldiers in camouflage hiding in the scrub near her house on the northern side of the border. Guns on stands, pointed at the road, ready for action.

“My dad always used to say keep your head down, don’t look at anybody, just keep walking,” Fiona told

“I look back and think that is actually insane, that is not normal, but that was normal.”

Fiona, 30, now lives in Sydney. The border she speaks of is all but invisible. The military barracks and guard towers are gone, as are the armed patrols, but the scars among the locals still remain.

The sectarian bloodletting of the Irish Troubles claimed more than 3600 lives over three decades. It only stopped in 1998 with the Good Friday peace pact, which ended the deadly campaigns of Sinn Fein’s IRA allies and the pro-British loyalist troops.

But now, 20 years on, that hard-won peace is in peril as the fallout from Brexit raises the threat of those border posts returning, disrupting free movement over the 500km border, with Ireland once more becoming a divided state beset by violence.

The countdown is on. The UK is due to leave the European Union on March 29, 2019. The Republic of Ireland, home to 1.8 million people, will remain in the EU. That’s only eight months away.

For the past 20 years people on the north and south of the Irish border have been able to move freely.

But there’s a huge question mark whether that can continue post Brexit.

In eight months time, will a border be imposed? Will friends and family from either side of the border suddenly need a passport to visit?

And perhaps the biggest question: If a border is imposed, will the bloody battle to reunite Ireland begin again?

These questions are hanging over the head of British Prime Minister Theresa May.

She has said that the legacy of Brexit will not be a hard border with the EU.

But it is difficult to see how she can achieve this, as one of the biggest reasons British people chose to leave Europe was to take control of their borders, and not allow in people freely.

If the UK is to honour that wish, they need to create a land border with the republic of Ireland.

Mrs May is stuck. She will now allow an exemption for Northern Ireland from Brexit. They have to leave Europe’s shared customs union and single market.

There’s been talk of a ‘soft border’, but any talk of a border is worrying locals.

They want to know how the UK government intends to protect the 1998 peace agreement and that’s not yet been made clear.

“At the end of the day a border is a border, whether it’s soft or hard,” Ms Strain said.

“The whole peace process was to get rid of the border and get rid of the grudge between Northern Ireland and the south of Ireland.

“It will just whip up all the troubles again. It definitely will. I know it will.”

Her concerns are shared by Northern Ireland’s top police officer George Hamilton, who believes a fortified hard border will be seen as “fair game” by terrorist groups who think the peace process is a betrayal of Republican ideals.

“The new IRA themselves have come out saying that — they have talked about Brexit being an opportunity for them,” he said.

There were five serious attempts by dissident Republicans to kill police last year, including one in Belfast in which two officers were wounded. Hamilton suspects there are more to come.

“A hard border from a policing perspective would not be a good outcome because it would create a focus and a target,” he said.

Tension has been growing since Britain voted in 2016 to exit the EU. London and Dublin have found themselves at odds, and faultlines are emerging between the largely Protestant Unionists, who want to preserve Northern Ireland’s place in the UK, and the mostly Catholic Republicans, who want Northern Ireland to join the Republic.

“I was brought up to get along with the other side because my mum and dad lived in Northern Ireland so we had more chance of a Protestant being our next door neighbour,” Ms Strain said.

“I have friends from the south of Ireland who only ever went to Irish school and have only ever associated with Irish people and they don’t have time for the other side.

“It is still very raw.”

Ms Strain worries about her parents. They still live in the house she grew up in, on the edge of Newry, which is part of the UK, while her cousins — only a few minutes’ drive away — live in the Irish Republic.

“Will we need a visa to visit them?” she asked.

“The police will be there and you’ll have to show your passport and all you want to do it is go to the shops at the end of your street.

“That is how surreal it is but that is what will happen.”

Among people living along the border, the threat of Brexit is already affecting local livelihoods.

Research has found people are being refused bank loans or won’t apply to universities in the UK. Businesses have relocated to the other side of the border or are holding off on employing more people. Others have put new jobs on hold.

Questions are being asked about how emergency services will cope and what will happen to children from Belfast who need surgery in the brand new purpose built facility in Dublin.

“Politicians underestimate the political, psychological, emotional, social, cultural and economic significance of the border,” says the report’s author, political sociologist Katy Hayward from the Queen’s University Belfast.

She says the peace process is a “fragile thing” that can be easily undermined.

Only last month, the border town known as Derry by Catholics and Londonderry by Protestants was gripped by six nights of street violence — the worst riots in Northern Ireland in years.

Bricks, bottles and petrol bombs were thrown as police fired baton rounds to break up crowds. Children in poor Catholic neighbourhoods, some as young as eight, were being taught how to make petrol bombs and lob them at cop cars.

Ms Strain says the dissidents are “the ones who don’t want to give up”.

“If this border goes through, then this group will get bigger and the whole feud will start up again. Everyone thinks it.”

There is little doubt that a hard border will be a visible, daily reminder of difference and politicians are playing a dangerous game in a place where frontiers and violence are inextricably linked.

“It provides a barrier to goodwill, especially if there are issues of migrants,” says Sydney University academic Luke Mansillo.

But he believes any violence will “take time to develop” and there are far more immediate consequences for the border, which currently notches up three million crossings a month.

“It will be a trade issue impacting companies that do manufacturing within Ireland and other parts of the EU,” he says.

“Eighty per cent of trade going in and out of Northern Ireland would face some sort of control or tariff and we are already talking about an economically depressed area.”

Yet a hard border is all but inevitable if Northern Ireland leaves the single market and after months of silence on the issue, locals fear the worst. They know from recent history that poor people who feel marginalised and sidelined are fertile ground for recruiting dissidents.

“I definitely, 100 per cent think that if that border goes up that the feud will go straight back up again,” says Ms Strain.

“And if that happens then everyone should feel scared.”