The most senior British soldier killed in Afghanistan had complained a shortage of helicopters was endangering troops, it has emerged.

Lieutenant Colonel Rupert Thorneloe - who died in July when his convoy was hit by an improvised explosive device (IED) - sent a memo less than a month before his death saying helicopter movements in the war-torn country were "not fit for purpose".

A series of dispatches was sent by the Welsh Guardsman, from Kirtlington, one which was headed "Battle Group Weekly Update" and read: "I have tried to avoid griping about helicopters - we all know we don't have enough.

"We cannot move people, so this month we have conducted a great deal of administrative movement by road. This increases the IED threat and our exposure to it."

Col Thorneloe goes on to detail how he had "virtually no" helicopters of the type which would allow him to move troops by air rather than road. He adds: "The current level of helicopter support is therefore unsustainable."

The 39-year-old adds in a dispatch that the system used to manage helicopter movements in Afghanistan "is very clearly not fit for purpose". Col Thorneloe, who was commander of the 1st Battalion Welsh Guards, died with Trooper Joshua Hammond on July 1 when their convoy was hit by an IED in Helmand province, north of the town of Lashkar Gah.

His death was the most senior British military casualty since the Falklands War.

Helicopter and other equipment shortages have become an increasingly controversial issue for the Government as casualties have mounted in Afghanistan.

Three weeks after Col Thorneloe's death, Prime Minister Gordon Brown dismissed suggestions that British lives were being lost because of a shortage of helicopters.