A SAILOR who went on a murderous rampage with a semi-automatic rifle on board a nuclear-powered submarine because he held a grudge against his superiors has been jailed for at least 25 years.

Able seaman Ryan Donovan, 23, admitted killing Lieutenant Commander Ian Molyneux, 36, instantly with a shot to the head as he ran amok on HMS Astute, which is normally based at Faslane, while it was docked in Southampton. He was given a life sentence.

Lt Cdr Molyneux, a father of-four, bravely tried to tackle Donovan after hearing shots from the SA80 rifle.

Donovan’s “murderous onslaught” was only ended when the leader of Southampton City Council, Royston Smith, and its chief executive, Alistair Neill, wrestled the weapon from him.

Donovan, a navigator yeoman, also pleaded guilty to trying to murder Lieutenant Commander Christopher Hodge, 45, whom he shot in the stomach.

But his real targets, whom he also admitted attempting to murder, were Petty Officer Christopher Brown, 36, and Chief Petty Officer David McCoy, 37. He had blasted at the pair from 10ft in a corridor four times but missed.

Donovan had been drinking while ashore and had volunteered for guard duty when onboard, because he was intent on killing the two petty officers who had reported him for disobeying a direct order to clean a part of the submarine.

Donovan had been told he would not be leaving the submarine for an attachment on another vessel because of his behaviour, and had become angry, the court heard.

The amateur rapper, who called himself Reggie Moondog, was given the weapon and 30 rounds by PO Brown.

He turned the gun on him and CPO McCoy but the men evaded his shots.

Then weapons officer Lt Cdr Molyneaux turned up and a witness heard him say: “What have you done?” seconds before he was shot.

Prosecutor Nigel Lickley QC said: “There appears to be no reason at all that he chose to shoot Lt Cdr Molyneux other than the officer was trying to stop him. There was no history between them, they did not work together.”

Donovan then moved into HMS Astute’s control room, which was full of local dignitaries visiting the vessel on a five-day goodwill visit to Southampton’s Eastern Docks.

Onlookers saw Donovan come with the gun at waist height and shoot Lt Cdr Hodge with a “wild” expression on his face.

Donovan was then wrestled to the ground by Mr Smith and Mr Neill and the gun went off harmlessly.

“There can be no doubt they displayed remarkable courage that day -- acting against an armed man,” Mr Lickley said.

Mr Neill described Donovan as he entered the control room.

He said: “The look on the face was of someone whose head was in another place, like they were in a dream, like they were in a faraway place, like they were doing this in a video game.”

Donovan told detectives: “I just felt that everyone was out to get me.”

In mitigation, Christopher Parker QC said Donovan, from Hillside Road, Dartford, Kent, who had joined the navy in 2008, wanted to murder on that day and then he wanted to kill himself.

Passing sentence, Mr Justice Field called the shootings a “murderous onslaught”.

He said it had been a “miracle” he had not killed the two petty officers before Lt Cdr Molyneux came from the control room to investigate.

“You backed away and, undeterred by the danger confronting him, Lt Cdr Molyneux moved forward to apprehend you and you shot him in the side of his head,” the judge said.

“In killing that officer, you robbed him of a bright future within a loving family.

“The consequences for his wife Gillian and his four children are immeasurable.”

Mr Lickley said the shooting spree had long been planned.

The previous year Donovan had told a colleague he was trying to “create a massacre in the control room” and the pair had discussed the computer game Grand Theft Auto, in which players took part in a “kill frenzy”.

As he went back to the submarine to start his duty on April 8 he told another crewmate, Colin Banks: “I am going to kill somebody.”

He also used to make “gangsta rap” music and boast he would be famous.

Donovan will serve at least 25 years and 194 days until he is eligible for parole.