A republican convicted of murdering a British soldier 18 years ago may be out within two years under the terms of the Good Friday Agreement.

Declan Duffy (36), who was brought to England from Northern Ireland to face the charge, pleaded guilty to murder when he appeared at Stafford Crown Court yesterday.

He was jailed for life with a minimum of 24 years.

However, he could serve a maximum of just two.

Sergeant Michael Newman (34) was gunned down by the INLA outside an Army recruitment office in Derby city centre on April 13, 1992. The terror group, which announced it was disbanding last year, admitted responsibility for Sgt Newman's killing at the time.

Fellow INLA member Joseph Magee was jailed in 2004 after pleading guilty to the murder.

Anthony Gorman, who is also accused of the shooting, is fighting extradition from the Irish Republic.

Jailing Duffy, Mrs Justice Macur described the murder as a “heinous crime”.

“You are a man, still young, with a violent past of using firearms to further the aims of your once affiliation to the INLA and your own criminality,” she said.

Duffy was only 18 at the time of the murder but Mrs Justice Macur said he was just as guilty as whoever pulled the trigger.

Flanked by three prison guards, Duffy stared impassively towards the judge as the sentence was read out.

In the public gallery, Sgt Newman's fiancee at the time of his murder, Elizabeth Robinson, his ex-wife Dawn Boyle and their daughter glared at the defendant, who sat behind the glass screen throughout the 90-minute hearing. All three later left the court without commenting.

A spokesman for the Sentence Review Commissioners said that Duffy is entitled to apply for his sentence to be cut in line with the Good Friday Agreement, and be heard by a three-commissioner panel, although added: “The INLA is now not listed under our eligible groups as it was disbanded last year.”

Duffy went on record last year to denounce the organisation.

In court, prosecutor Michael Atkinson said it is still not known whether Duffy or 39-year-old Gorman shot Sgt Newman.

Defending, Nigel Leskin said Duffy expressed “deep regret” for the murder.

Speaking after the sentence, Detective Chief Superintendent Andrew Stokes said: “I am glad that Declan Duffy has finally admitted his part in this.

“We realise it must be very difficult after all these years for these things to be dragged up again but at the same time, for his family's sake, it is vital that we are able to bring the men responsible for this murder to justice.”