Declan Duffy: A life of violence

Declan Duffy being led into a Dublin court in 2008

At 36, Declan "Whacker" Duffy, who on Thursday admitted killing a British army sergeant 18 years ago, is already considered a veteran republican paramilitary.

He was still a teenager when he was involved in the murder of Sergeant Michael Newman in Derby in 1992.

Originally from Armagh, Duffy joined the Irish National Liberation Army (INLA) in the 1980s.

The INLA was a familiar name on news bulletins throughout the Troubles in Northern Ireland.

A much smaller group than the IRA, it was given to high-flown socialist rhetoric while indulging in bloody bouts of feuding.

It retained a capacity for ruthless killing and was behind some of the most high-profile murders of the period, including that of Conservative MP Airey Neave.

The INLA is believed to have been responsible for 111 murders from its formation in 1975 until its ceasefire in 1998.

And although on ceasefire, it is still thought to have been involved in a number of murders since then.

Duffy, who has admitted killing Sgt Newman, is currently serving a four-year jail sentence in the Irish Republic for the INLA membership.

He was moved from a jail in the Irish Republic, where he has been living for a number of years, to one in Northern Ireland, from where he was finally moved to England for trial.

In Dublin, it is believed he was head of an INLA unit that was involved in criminal gangland activity.

Duffy was a teenager when he murdered Sgt Newman

In 1999, he led a group which took six members of a rival criminal gang hostage in what was to become known as the Ballymount Bloodbath.

The hostages were beaten and tortured at the Ballymount Industrial Estate in Dublin, but one managed to use his mobile phone to call for back-up.

In the ensuing brawl, INLA man Patrick Campbell was killed in a machete attack.

A member of the criminal group was shot dead in a revenge attack.

Duffy was convicted of false imprisonment and possession of a handgun and served nine years in prison. He was released in 2007.

In recent years he has been arrested a number of times by police in the Irish Republic, once following a stabbing and another involving the kidnap and torture of a man.

In both instances the victims either withdrew their statements or refused to make a complaint against Duffy.

Gangland feud

Newspaper reports from Dublin suggest he has also been involved in a feud with a gangland figure known as "Fat" Freddie Thompson.

In 2009, Duffy admitted membership of the INLA but at the same time publicly disassociated himself from the group.

He was sentenced to serve four years in Portlaoise Prison, County Laois.

Speaking to the Irish News last year, Duffy said he was keen to move his family back to Northern Ireland and that he had turned his back on his paramilitary past.

He said he hoped to serve the remainder of his INLA membership sentence alongside any sentence he would receive for the murder of Sgt Newman.

However, members of his family have suggested that the INLA may deny Duffy was ever a member of the organisation, which would make him ineligible for early release under the terms of the Good Friday Agreement.