Marine Wigley died in Helmand Province in December 2006
Human error was partly to blame for a Royal Marine's death from "friendly fire" in Afghanistan, a coroner has recorded in a narrative verdict.
Jonathan Wigley, 21, from Hook, Hampshire, was hit by gunfire from a US jet during battles with the Taleban in Helmand Province in December 2006.
He died almost instantly from severe chest wounds while lying in a ditch.
Assistant deputy coroner for Oxfordshire Andrew Walker praised the US for co-operating with the hearing.
Mr Walker, who has held dozens of inquests into the deaths of British military personnel killed in Afghanistan and Iraq, has previously been critical of what he says is the lack of help from the the US.
The inquest heard evidence from a US investigation into the death which described how the pilot of the F18 aircraft - identified only as Pilot One - made the mistake.
I must say how grateful I am to the Ministry of Defence for their efforts in securing the co-operation of the United States
Andrew Walker Assistant Deputy Coroner
Marine Wigley's inquest was the first where such information was made readily available, Mr Walker said, but Pilot One did not give evidence.
During the inquest, the court heard the American jet mistook members of 45 Zulu Company 45 Commando Royal Marines for insurgent forces situated 430m (470 yards) away.
Their positions, near a strip of trees and Taleban compounds, were very similar, Mr Walker said.
But he added the process of attacking ground targets from low-flying aircraft was very complex.
"I must say how grateful I am to the Ministry of Defence for their efforts in securing the co-operation of the United States in allowing coroners to see material that, prior to this inquest, could not be seen," he said.
"I am very grateful to the Ministry of Defence, and indeed to the United States, for their co-operation in this inquest."
Earlier, Mr Walker praised the bravery of Marine Wigley's colleagues on the day of the incident, in particular the medical team who set off to collect him while coming under heavy fire.
In a statement released after the verdict his parents, Clive and Sharon, said they agreed with Mr Walker.
"We would like to thank those who tried to save Jonathan. We wish to thank those who gave live evidence, in particular those who were there on 5 December 2006, and we know how difficult it was for them to do that."
A spokesman for the Ministry of Defence (MoD) said: "We have noted the coroner's comments and will consider these alongside the findings of our own investigations, to ensure that we learn lessons from this tragic incident."
Marine Wigley was born in Melton Mowbray, Leicestershire, and grew up in Grantham, Lincolnshire.
Marine Wigley's parents had waited more than two years for the inquest
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