Officer C told the inquest jury in Hull he also believed Mr Murden, who was carrying a sword, was a threat to members of the public at a nearby garage when he fired nine shots from a carbine.

The police officer was sent to the incident, in March 2005, with another officer after reports that the 26-year-old charity worker was walking along the A63 near South Cave, west of Hull, possibly carrying a firearm after driving the wrong way down the road and crashing his vehicle.

Messages relayed to them on their way to the incident included that Mr Murden has possibly taken a sword from his bedroom and also a report from a passing motorist that he possibly had a crossbow or a semi-automatic weapon with him.

They were also told he had suffered a psychotic episode after taking drugs.

The officers stopped when they saw Mr Murden on the westbound carriageway, near a Little Chef restaurant and a petrol station.

Officer C described him as walking fast towards them ‘with a purpose’ and cradling his arms, although he could not see what he was carrying.

When Mr Murden was about 15 yards away, he drew a sword with his right hand and held it up in the air as if to bring it down to someone in an attack.

Officer C told the inquest he heard Officer D fire two baton rounds at Mr Murden and saw each one strike, but that they had no effect.

“I honestly believed the life of my colleague was in threat, and if he got past Officer D the lives of the people on the forecourt would be in danger,” he said. “I decided I would have to use my conventional weapon.”

The officer fired an initial two shots but they seemed to have no effect, he said. He fired another two but Mr Murden kept coming towards them, so he fired another two shots.

The charity worker’s legs gave out but then he began to get up again, the officer told the inquest.

“The position that Simon was in is called a lunge position, where you can quickly launch yourself off the floor,” he said. “I’m thinking, he could get to me very quickly here. At that point, I thought I was going to die. He’s 10 feet away from me, his arms were outstretched with the sword pointing straight at me.

“I honestly thought I was going to die that day.”

Officer C fired another three shots and this time he said Mr Murden did not get up. His three fellow officers then began resuscitation attempts.

Michael Topolski QC, representing Mr Murden’s family, told the inquest that the shots were fired in less than 50 seconds and suggested that the officers acted in haste.

“This was all too rushed, you gave yourself no thinking time at all,” he said.

Mr Topolski asked if Officers C and D considered warning members of the public at the garage.

Officer C said: “If we had let Simon walk up to the garage forecourt he could have killed or maimed members of the public.