Three Royal Marines, including a Shropshire soldier, were killed in Afghanistan by a 13-year-old suicide bomber who carried his explosives in a wheelbarrow, an inquest heard.

Army standard operating procedures have since been changed to include children in stop and search checks following the death of Marine Damian Davies, of Telford, and his comrades.

Marine Davies, 27, from St Georges, was guarding a bridge, near Sanguin in southern Helmand Province, with Sergeant John Manuel, 38, and Corporal Marc Birch, 26, when they briefly stepped out of their armoured vehicles, the inquest heard yesterday.

As they stood together discussing tactics the boy ran up to them pushing a wheelbarrow and detonated a huge bomb.

The force of the explosion blew Sgt Manuel and Cpl Birch straight off the bridge and into the water while Marine Davies died later at Camp Bastion.

The blast happened on December 12, 2008, as the men helped to secure an area around the new Forward Operating Base, near Sanguin.

Marine Jonathan Selisney, who was driving a fourth armoured vehicle and decided to stay in his Vector while the others stepped outside, told the hearing: “After about five minutes out of the corner of my eye I saw a young boy running. It all happened in a split second but it looked like he had done something wrong and was running away.

“Then there was a loud bang and a big cloud of black smoke.”

An unnamed Afghan farmer, who witnessed the scene and was seriously injured in the blast, told the inquest in his witness statement that he had seen the boy approaching the group.

He said: “He was a young boy with no facial hair or beard. He came to the side of the stream beside the soldiers and was pushing a wheelbarrow.”

Major Graham Smith, from the Special Investigating Branch, revealed there had been a change in standard operating procedures in relation to stop and search.

All children and their belongings were now given the same full searches when passing through check points in Afghanistan as adults, he said.

Major Smith added: “Prior to this occasion there had not been any other incidents of insurgents using children with wheelbarrows to detonate explosives and, to the best of my knowledge, there have been no later incidents since this occasion either.”

Mr David Masters, assistant deputy coroner for Wiltshire and Swindon, recorded a verdict that the men were unlawfully killed while on active duty.

By Simon Hardy