Grid co-ordinates communicated between an air controller and an American weapons officer "did not marry up" before a 500lb bomb was dropped from a US aircraft killing three British soldiers in Afghanistan, an inquest heard yesterday.

Naomi Gornall

Grid co-ordinates communicated between an air controller and an American weapons officer "did not marry up" before a 500lb bomb was dropped from a US aircraft killing three British soldiers in Afghanistan, an inquest heard yesterday.

Privates Aaron McClure, 19, Robert Foster, 19, and John Thrumble, 21, were under intense fire in Helmand when a US F15 aircraft, called to help, dropped the bomb on them instead of a Taliban position one kilometre further north.

Pte McClure, from Ipswich, Suffolk, Pte Foster, from Harlow, Essex, and Pte Thrumble, from Maldon, Essex, of 1st Battalion The Royal Anglian Regiment, died in the blast on August 23, 2007, the inquest at Trowbridge Town Hall in Wilts heard.

Privates McClure and Thrumble were on the roof of a compound and Private Foster was in the house firing from a window when the order to strike was given by their platoon commander Major Antony Borgnis.

Sgt Mark Perren, a forward air controller, passed on the order to the Weapons Support Officer (WSO2) aboard the US aircraft.

Coroner David Masters said: "He (Sgt Perren) explains the problems and difficulties, for instance he had no head set, no head sets using a hand set to undertake that communication.

"Performing these tasks on his own. We will deal with distractions but most relevantly he will deal with the grid references which were provided by him and the communication with the WSO2 who provided him with the grid references as well and the grid references did not marry up.

"We will deal with his non delivery of what is described as a nine liner giving all the requisite information to assist the Americans.'

A nine liner is a document which sets out the requisite information needed by the WSO2 whose role it was to drop the bomb.

He added: "There was an incorrect clarification of the grid references.'

Sgt Perren was investigated but no charges were brought against him, the inquest heard.

It was heard how the blast instantly killed Private McClure and Thrumble and seriously injured Corporal Stuart Parker and Private Joshua Lee.

The area was evacuated and once everyone had returned to the operating base they realised Private Foster was not with them. Some of his colleagues went back to find him and it was heard that they used their bare hands to search for him in the rubble.

He was eventually found and had sadly died of asphyxia as a result of entrapment, according to a post mortem.

Private McClure, Thrumble, Lee and Corporal Parker had all taken up fighting positions on top of the roof when the bomb hit, however Private Foster had been firing shots from the window inside the house. The blast caused the roof to collapse.

Since their deaths there has been various official inquiries conducted including one by the American Forces called the combined investigation board report.

The coroner explained that the report includes transcripts from the cockpit, voice recording and a verbatim transcript of witnesses who had assisted the report.

Mr Masters explained that he had only just seen this part of the report and had not been allowed to take notes or remove it.

Corporal Parker's solicitors requested a copy of the report to the American Embassy under the Freedom of Information Act. The version released by them does not include the cockpit recording or identifies the pilot.

Mr Masters explained that because there was such a wealth of useful information contained in the report, it was only fair that all those involved see a copy before the full inquest can proceed.

He said: “It means that we are not going to be in a position that everyone wanted, including me, to do this inquest before Christmas, and I very much regret that.”

The inquest is expected to be adjourned until February next year.

Speaking outside the court Private McClure's uncle Allan, said: “We don't care how long it takes. We will do whatever it takes, we just want the truth about what happened.”

Among those in attendance was Private Thrumble's mother Pearl, Private McClure's mother Lorraine and father Karl Smith, his uncle Allan and Private Foster's family, John Foster and Lisa Walker.

Among those expected to be called as witnesses will be Sergeant Perrin the Force Air Controller who dropped the bomb. Although Sergeant Perrin was under investigation by the army this charge was not pursued.

The inquest will deal with matters relating to Sergeant Perrin's training, his instructions and the communication with the Command Support.

The coroner said: “He [Sgt Perrin] had no head set while using a hand set to undertake that action. He was performing these tasks on his own.”

The inquest will also look at the incorrect verification with the grid references given to Sergeant Perrin and a series of other failings by the air crew and the Force Air Controller.

Mr Masters said the inquest will also look at whether there was a “loss of situational awareness by them - the American officers”.

Before the hearing started, Hilary Meredith the solicitor for the three families of the dead soldiers as well as two injured soldiers, Stuart Parker and Joshua Lee, made a statement questioning why the incident happened.

“First and foremost the families are here to support their boys, as are Stuart Parker and Joshua Lee.

“We want to find out why in today's modern warfare mistakes like this can happen. It should not happen and we want to make sure it is prevented from happening again.”

Mrs Meredith said the families had hoped the inquest would be completed before Christmas.

Captain Ian Robinson, welfare officer for the Ist Battalion the Royal Anglian Regiment, said: “The families have asked me to issue a short statement on their behalf.

“Today is a very painful day for all the families who are focussing on their sons' tragic deaths. They also want everyone to know their thoughts and prayers are with the family of Lance Corporal Drane, who was killed last week in Afghanistan.”

The inquest was adjourned until a date to be fixed in the New Year.