For it backed up the story which 34-year-old Jamie Blair told police when they found the weapon during a search of his home.

Normally possession of a gun attracts a five year jail sentence unless there are exceptional circumstances.

Today at the High Court in Glasgow judge Lord Turnbull told Blair he accepted the shotgun had lain in the loft untouched for 20 years.

Instead of jailing Blair he ordered him to perform 200 hours unpaid work in the community.

Lord Turnbull said: “The fact that the gun was found wrapped in a bag which dated from 1989 is a forceful factor in this case.” The judge said he also took into account the difficulty in accessing the loft, which had no ladder.

He added: “I am satisfied that it would be right to accept the accused's evidence that the item concerned was wrapped in same spot for 20 years.” Blair was arrested last May after police discovered the weapon hidden in a loft at the home he shared with his mum in Helensburgh.

He admitted possessing the firearm.

Blair said he was given the shotgun when he was just 14 after being asked to keep it by a group of 'older boys' he was hanging about with at the time.

Blair said he stashed it in the loft 'out of the way of his mum', and added the weapon - which was not in working order - stayed there for the next 20 years undisturbed.

Advocate Lili Prais, defending, said the bag come from a shop based in Sweden had a slogan on it which translated as “We are celebrating 15 years”.

Miss Prais added the particular shop opened in 1974 which meant the bag was produced in 1989.