The Belfast agreement brought to an end a conflict that claimed over 3.5 1000 lives.

The loyalists move comes amid a row this week over trading rules and a wider push for a referendum on Irish unity from the main nationalist party.

Sinn Fein.

Fergal Keane has been gauging reaction amongst unionists.

The echoes of the past are being summoned forth, the old fear of the union broken of being sold out to the Catholic South in our province.

Please stay ever.

Never, Never, never.

But the troubles have ended.

The power of the Catholic Church has faded away.

The southern government speaks of respecting unionist fears.

I don't believe the future of the island of Ireland is about majoritarian is, um in the crudest sense.

I think it's about consensual relationships.

Trust they started, gets it.

But soothing words don't reassure loyalist politician Billy Hutchinson, who feels Irish nationalism is advancing against divided unionists.

I think He served 15 years in jail for murdering two Catholics during the Troubles, but later became an advocate of the peace process more than 20 years after the peace agreement.

It's a measure of enduring mistrust here that for him, Irish unity would mean victory for Sinn Fein, the party that spoke for the IRA.

If we were to live in a 32 county Ireland, I would imagine some of that power would be a decentralized and devolved powers, decentralized to an Ulster, where it was six counties and in counties.

We would feel persecuted because the people who would have the power would be shin faint.

I think I am right in saying we are the most loyal part of Great Britain.

But 100 years after the foundation of a unionist ruled Ulster at the heart of the British Empire, that world has been changed by the troubles by demographics and global transformation.

Belfast City of 1000 launches The industrial muscle of the unionist working class is gone, memorialized in popular art where thousands once labor to build ships like Titanic, Amazon now employs dozens.

In this time of change, I wondered what a younger generation of unionists might feel about the prospect of a united Ireland.

Sarah Crichton is a lawyer, left wing in her politics and avowedly pro union.

I don't know where I fit in.

Where do I fit in any united Ireland?

You know I'm British.

I'm Irish as well.

But it is something that worries me.

It worries me, I guess not so much the idea that happening, though obviously I don't want it to happen.

It's that it happens and with no plan, we don't know what's going and what it's going to look like.

There's no physical frontier on the island anymore.

But among many rural Protestants, the long memory of killing has left deep wounds.

This is the Orange Hall at all to have a three miles from the border, a frequent target of vandalism.

It has a beleaguered air.

Six Protestants were murdered here at the time of Ireland's partition 100 years ago, and this 15 minutes drive away is Kings Mills, scene of a more contemporary massacre.

10 Protestant workmen were lined up by the roadside and shot dead by the IRA in 1976.

It was a sectarian retaliation for the killing of local Catholics.

Kenny Warden hit two week girls.

The only toddlers, Alan Black was the only survivor, and that was his whole world.

What comes back, if I can ask you Uh huh, my 18 year old apprentice screaming for his mommy and a gunman coming over and blowing his face away.

And he was shedding.

Mommy, Mommy, Mommy, that comes back.

That comes back off With all this talk of a border poll, I've met people and made a lot of Protestants who are unsettled, fearful of what might be coming.

What do you feel about it?

I am not fearful if if a border poll well, it's like it's like everything else, Brexit or anything else, whoever votes for it and get it.

I'm a unionist by nature, but I'll take whatever is voted on.

Whatever the vote is, a poll isn't imminent and predicting a result not possible.

But there is no certainty that the ties which defined their identity will endure for the generations to come.