Mr Justice Hidden at Wolverhampton Crown Court told James Robinson, 28, of Oak Drive, Ellesmere, that the shootings had been "evil and wicked".

He recommended Robinson serve at least 18 years before being considered for early release.

Robinson admitting the murder of Andrew Gardner, and the attempted murder of Pat Tranter and Neil Roberts, at his house in Ellesmere, Shropshire on 3 August last year.

Overpowered by unarmed man

He also admitted the illegal possession of a sawn-off shotgun and possession of a 9mm Beretta pistol with intent to endanger life.

Mr Gardner, 36, of Irby, Wirral, died instantly when Robinson, a shooting club range officer, opened fire on the three investigators after they found missing mail and an illegal stash of bullets in his bedroom.

Mr Tranter, 53, of Blacon, Chester - who was in court to hear the sentence - required major surgery after being hit by four bullets.

Mr Roberts, 31, who avoided injury although he was shot at twice, overpowered Robinson at the scene.

Outside the court, Mr Gardner's widow Fiona called for tighter controls on guns, saying that Robinson would have turned the Shrosphire market town into another Dunblane or Hungerford, had he not been overpowered.

'Worst year of my life'

The dead man's brother, Tony Gardner, said: "We are satisfied that justice has been done."

Mr Tranter added the jail sentence had brought to an end the worst year of his life.

He said: "Not a day has gone by without me reliving some part of that dreadful morning. I will never forgive Robinson for what he did."

Detective Chief Inspector Clive Harding, who led the investigation, said afterwards that there had been no hint until that day that Robinson was a dangerous man.

Robinson, who had worked for Royal Mail in Ellesmere for three years, came under investigation in early 1998 after complaints of missing mail.

Bullet box

A number of postal sacks were found on a council tip in Oswestry and Robinson admitted theft of mail during an interview.

He agreed to allow the three investigators to search his home.

"While searching Robinson's bedroom, Pat Tranter came across a box containing bullets and he told Robinson that the police would have to be called," said Mr Harding.

"At that point Robinson suddenly produced a pistol and started to fire.

"Although he was being fired upon, Neil Roberts launched himself at Robinson. He grappled with Robinson, taking him out on to the landing and the two men tumbled down the staircase.

"Only when they reached the front door was Mr Roberts able to wrestle the gun from Robinson and restrain him."