Former Irish republican prisoners say they fear loyalist gunmen will react violently to the prospect of a united Ireland.
Between 1969 and 1998 more than 3,000 people died during The Troubles as Irish republican terrorists tried to force Britain to give up Ulster and allow a united Ireland.
Loyalist Protestant gangs like the Ulster Volunteer Force (UVF) and Ulster Defence Association (UDA) carried out hundreds of killings as they clashed with the Provisional IRA and the socialist INLA.
Don Browne, a former INLA man who spent 14 years in prison, says: “The Good Friday Agreement got me out of jail, so I certainly support it. The Irish do not have a border problem It’s a British border. We have never recognised it. We are the occupied six counties.”
His friend Paul, who served time for possessing petrol bombs, says: “The loyalist paramilitaries will start killing Catholics if a united Ireland ever looks likely. They are still there and they are up to their necks in drugs and drug dealing. When their backs are against the wall they always carry out sectarian killings.”
Mr Browne, 60, said things had changed a great deal since the 1990s but he said there were paramilitaries on both sides who were itching to restart the conflict.
In April this year Lyra McKee, a 23 year old journalist and blogger, was shot dead as she watched rioting in Derry’s Creggan estate.
Mr Browne said he had met and been interviewed by Ms McKee, who he described as “lovely”, but he said she had simply been standing in the wrong place and had not been deliberately targeted by gunmen from the New IRA.
The New IRA’s political wing, Saoradh, have an office around the corner from the ex-prisoners’ centre but they were not available for comment when a Sputnik reporter called on them on Friday.
Mr Browne says: “I am a republican but I am not a practising republican. I would not say to Saoardh you are doing the wrong thing. For me to criticise them for being active republicans would be the wrong thing.”
Another former IRA member, nicknamed Sauce, said he doubted Saoradh had the “will of the people” on their side for a continued armed conflict.
Under the Good Friday Agreement the British government can call a border poll if it believes the majority of people in Northern Ireland are in favour of a united Ireland.
Paul, who lives in County Mayo, says: “I would not be surprised if there is a border poll. But as a socialist I don’t give a toss about a capitalist united Ireland.”
Nearby is a museum and shop run by the Irish Republican Socialist Party (IRSP), the political wing of the Irish National Liberation Army.
While the IRA and its political wing, Sinn Fein, signed the Good Friday Agreement the INLA never did, although it laid down its weapons.
The IRSP’s Keith Dunleavy says: “The INLA was totally against the Good Friday Agreement, although it stood down. But they said we are ready if it ever starts up again.”
Mr Dunleavy, who has recently returned from an official trip to Cuba, says: “There is no point having a united Ireland unless it’s going to be a socialist united Ireland.”
Most former paramilitaries are aware that a return to war will involved casualties in both communities.
Mr Browne was jailed for murdering an Ulster Defence Regiment soldier, whose son would later carry out one of the worst atrocities during The Troubles - the Greysteel “trick or treat” massacre in October 1993 - in revenge.
He says he does not believe the young people of Northern Ireland have any appetite for a return to hostilities.
Sauce agrees and said The Troubles started because Catholics were discriminated against and could not get jobs, which were reserved for Protestants, and struggled to get decent housing, especially in Derry.
“People were fed up with no work and they would got to England and find they could get a job over there easier than you could here,” Sauce says.
Nowadays sectarian discrimination is very rare and employers and landlords can be prosecuted if they put Protestants ahead of Catholics, or vice versa.
But Mr Browne says: “The IRA never went away, and it’s always recruiting, just in case.”
Local newspapers in Northern Ireland have reported heavily on the recent targeting of executives from the Quinn International Holdings business empire, reportedly carried out by criminals masquerading as republicans.