A Royal Marine had been in Afghanistan for just two months when he was shot dead while providing cover for his fellow soldiers, an inquest has heard.

Lance Corporal Martin Gill, of Plymouth-based 42 Commando, was shot in the neck and head while on foot patrol in the Nahr-e-Saraj district of Helmand province on June 5 last year.

An inquest at Nottingham Coroner's Court yesterday heard how at the time of his death the 22-year-old was cover man while other Marines carried out biometric data checks on local Afghans. He had been in Afghanistan for two months and had been on various foot patrols.

L/Cpl Gill, who was known as Fish to his comrades, was near the back of his patrol, leaning against a wall in a seated firing position, with his weapon in a "prone position" resting on his knee just before he was shot.

Corporal Dearan Withall told the inquest the Marines were just about to move from their position having finished the biometric exercise. The exercise includes photographs, fingerprints and an iris scan being taken.

"That's when the loud noise of a weapon firing system from an enemy point opened up and all the earth and ground kicked up near our feet," Cpl Withall said.

"The first burst happened and I ran towards cover. As I ran towards cover I shouted 'contact left'. At that stage I turned to the left and I looked backed and saw another burst of rounds hit Fish."

L/Cpl Gill's younger brother, John-Daniel, and sister, Rebecca, as well as his girlfriend Lauren were present at the inquest. He had lost his mother to cancer just weeks before he was deployed overseas. His father had also died about 17 years earlier.

Cpl Withall said he thought L/Cpl Gill had been hit by the first round of bullets and was killed almost instantly.

He was given first aid and dragged by Cpl Withall and Mne Barry Bullman down a nearby alleyway and, with the help of other members of the company, carried over an irrigation ditch filled with waist-high water before being evacuated by helicopter.

The inquest heard that a post-mortem examination found the cause of death to have been from a gunshot wound to the neck and head – areas that his body armour could not protect – and his injuries were not survivable.

Major Jason Durup told the inquest he believed the enemy would have seen the patrol crossing the ditch, reported it, and a shooter put in place as it made its way into the village of Adensee. He said he did not believe the shooter was there at all times.

No member of the foot patrol saw the shooter either before or after L/Cpl Gill was injured.

LCpl Gill grew up in Nottingham, where he lived with his brother, John, and his sister, Rebecca. His company commander said he became the "bedrock" for his brother and sister when their mother died.

Recording a verdict of unlawful killing yesterday, Miss Mairin Casey, the coroner for Nottinghamshire, called the Marine's death an ''appalling tragedy".

She offered his brother, sister and girlfriend her condolences and also paid tribute to the Marine's colleagues.

"You did everything you could to save his life.

"The evidence made it clear that was impossible," she said, adding that the family could take comfort in the knowledge that L/Cpl Gill did not suffer.