A ROYAL Marine from Plymstock died in Afghanistan after stepping on a 'legacy' bomb which could have been laid years before, an inquest heard.

Sergeant Barry Weston died from "catastrophic injuries" on August 30 last year after taking "two steps" out of a 'safe lane' – which had just been cleared for Improvised Explosive Devices (IEDs).

The marine, who had just become a father for the third time, had volunteered to deploy to Afghanistan at short notice, replacing a Royal Marine who himself had been blown up in an IED blast.

Yesterday's inquest at The Council House heard that, at the time of the incident, Sgt Weston was taking part in Operation Archer in a 'contested' area in Helmand province's Nahr-e Saraj district.

Bickleigh's 42 Commando Royal Marines was leading the operation with the unit's K Company split into three 'multiples' to carry out reconnaissance on a local mosque.

Sgt Weston and his men were tasked to provide 'over-watch' for the other multiples and organise crossings over irrigation ditches.

Point-man Marine Stephen Harrington had used specialist equipment to scan the ground for IEDs creating a 'safe lane' through 2ft to 3ft tall grass.

The inquest heard that at least four marines had walked up and down the route before Sgt Weston did so.

But instead of keeping to the checked route, the 40-year-old, known as 'Baz' to his friends and comrades, stepped into the grass and onto a wooden pressure plate.

Reading a witness statement by Mne David Fairbrother, who tragically himself died a month later in Afghanistan, Plymouth coroner Ian Arrow said: "I recall seeing Sgt Barry Weston returning along the safe lane from the crossing point.

"He took at least two steps outside the safe lane, and he was about two metres away from me.

"I saw him outside the safe lane, but it did not occur to me at first. No-one would intentionally step out from the safe lane."

The inquest heard witnesses then describe hearing a "loud explosion".

Some thought it was a grenade attack because a threat assessment had warned of the marines being engaged at "any time".

The inquest heard the blast created a crater one metre in diameter and about 12 inches deep.

Captain Chris Armstrong, who was K Company's Second-In-Command and Intelligence Officer at the time, added: "Because it was an artillery shell we believe it was a legacy device which had been in the ground for a very long time.

"The area was very overgrown. It would have been impossible for Baz to have seen the device. There were no ground signs."

Major Jason Durup, who was the Officer Commanding 42 Cdo's K Company last summer, defended the marines' actions.

"Sgt Barry Weston was a very competent and experienced senior Non-Commissioned Officer in the Royal Marines," he said.

"Despite the incident it's worth mentioning that there are a number of times throughout a tour when individuals have stepped out of the safe lane.

"It's just something that happens. We have all done it and nothing bad has happened."

Summing up the inquest, coroner Mr Arrow, said: "Momentarily, Sgt Barry Weston stepped out of the lane.

"I am satisfied that, at some point, this IED was detonated. Sadly, I think he set it off."

Recording a verdict of unlawful killing while Sgt Weston was on active service, Mr Arrow said it was likely the IED had been there for some considerable time.

He also said he believed Sgt Weston died "immediately".

Sgt Weston joined 42 Commando from Stonehouse-based 30 Commando in order to spend more time with his family – wife Joanne and daughters Jasmine, Poppy and Rose.