An explosives expert from Chorley was killed by a bomb in Afghanistan after it was missed by his search team, an inquest heard.
Warrant Officer David Markland, of 36 Engineer Regiment, died instantly when the device exploded on February 8 this year.
The father-of-two, from Euxton was leading a team from the Gurkha regiment, who were armed with metal detectors.
As the team searched the route for bombs, WO Markland followed closely behind, marking the route with spray paint to show it had been cleared.
But they missed a bomb buried in a ditch, possibly because it was encased in plastic, Preston Coroner's Court heard.
Sapper Bickey Gurung said: "I literally walked over that ditch and there was nothing, no indication."
The Gurkhas were used to clear the route because specialist equipment was damaged by an enemy device in a separate task.
The Task Force Thor equipment is normally used for the initial sweep of the area before bomb disposal experts are brought in, the court heard.
But the decision was made to carry on with the task regardless, the court heard, as this was usual procedure.
The blast destroyed most of the evidence but small fragments of plastic were found at the scene, Sergeant Gareth Reid told the coroner.
He was standing near WO Markland when the bomb exploded.
Sgt Reid told the coroner that the soldier kicked a stone immediately before the explosion.
"Dave seemed to be looking down at the time as he did it.
"I'm not sure if he took a step but I heard and I felt an explosion. I felt a blast and I felt dirt and stones from the ground hit me on the side of my face," he said.
Nicholas Hunt, consultant pathologist, said the officer died of "devastating head injuries associated with the amputation of his limbs".
He continued: "I give as the cause of death blast injuries caused by an explosion. Given the injuries obtained, his death would have been instantaneous with no knowledge of what happened. There is nothing that those around him could have done to save his life."
Deputy coroner Simon Jones ruled that WO Markland was unlawfully killed due to the explosion.
There is no way of knowing for sure what triggered the bomb, or why it went undetected, he said.
"We will never know whether the sweep missed it or whether it would not have been picked up by a metal detector.
"David Markland was killed while carrying out his duties which included making areas safe for his colleagues and the local population, a task which involved putting his own life at risk for others.
"I think it only right that we recognise that."
Speaking after the verdict, WO Markland's mother Annette said the task should have been stopped because the equipment was damaged.
"When the Thor broke they should have stopped and regrouped. If an armoured vehicle hasn't got a chance, what chance have they got?"
But she praised the search team who missed the bomb and shook their hands as they left the courtroom.
"David thought they were the best search team ever, he bragged about them. It is just such a waste of a life," she added.
WO Markland leaves behind wife Corallee and their two sons, Keelen, 10, and Logan, seven.
He was in the Army for 20 years and was on his eighth operational tour, having already served five times in Bosnia, once in Iraq and a previous tour of duty in Afghanistan.
He had been selected to be made a Field Squadron Sergeant Major just before his death.