A Territorial Army sergeant who was allegedly shot dead by a colleague was "larking around" with the weapon and "chuckled" seconds before the fatal blast, a court martial heard.

Sergeant John Nightingale, 32, of Guiseley, who suffered a fatal bullet wound to the chest while serving in Iraq in September 2003, had grabbed the SA80 rifle's cocking handle before it discharged a shot, the court heard.

His friend, Lance Corporal Ian Blaymire, has denied a manslaughter charge at a court martial in Catterick Garrison, North Yorkshire.

The defendant, a 23-year-old plumber from Leeds, wept as Military Police interviews were read out at the hearing yesterday.

He told Special Investigations Branch officers he had grown "complacent" about checking weapons.

He told them: "I just wish the safety procedure was better, because it was pretty slack really."

He had taken a friend's rifle to the armoury a coach ride away from their desert base to the Shabah Camp as a favour and denied deliberately pointing it at his unit commander, the court martial heard.

He told investigators he had put his own gun down before showing the other rifle weapon to Sgt Nightingale, whom he had known almost throughout his six years with the TA.

Blaymire said: "He (Sgt Nightingale) was talking to me about R and R (rest and recuperation) and then out of the blue he reached over to the weapon and grabbed the cocking handle to the rear, I think with his left hand.

"As he did this, for a second, I was a bit stunned at him grabbing the weapon."

Blaymire said the weapon was slung over his shoulder and the muzzle was pointing at 45 degrees to the ground, but it levelled at Sgt Nightingale as he moved backwards.

"I pulled away and stood back on my left foot and as I stood back, the weapon rose and a round came out of the chamber, shooting John in the chest and he fell onto the table."

He said the rifle did not have a magazine attached and he only realised afterwards there was a round in the chamber.

"I shouted 'No', I just couldn't believe it," he told investigators.

"As soon as I heard the weapon go bang I realised a round had come out of it."

As medics arrived to treat Sgt Nightingale, a former Otley Rugby Union player, Blaymire was led away. Later, Blaymire said Sgt Nightingale was in a good mood on that day and had grabbed his weapon on other occasions while in Iraq.

The TA driver said: "He was larking around. I presumed he thought the weapon was mine.

"I just remember after he did it, he chuckled to himself and within seconds the shot was fired."

The court martial, which has raised concerns about the level of training TA soldiers received before deployment in Iraq and which is in its sixth week, continues.