The British commanding officer who was killed in Afghanistan by a roadside bomb in July had only weeks previously warned that troops would die because helicopter shortages were forcing them to travel by road, it was reported last night.

In an e-mail sent to military commanders, Lieutenant-Colonel Rupert Thorneloe said that helicopter operations in Afghanistan were “not fit for purpose”.

Colonel Thorneloe, 39, Commander of the 1st Battalion Welsh Guards, died with Trooper Joshua Hammond on July 1 when their convoy was blown up by an improvised explosive device (IED) during a patrol north of Lashkar Gah in Helmand Province.

The colonel was the most senior officer to have been killed in the Afghanistan campaign.

On June 5, in his “Battle Group Weekly Update” to the Ministry of Defence, he wrote: “I have tried to avoid griping about helicopters — we all know we don’t have enough.

“We cannot not 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.”

Colonel Thorneloe wrote that he had “virtually no” helicopters of the type needed to move troops by air rather than road. He wrote: “The current level of SH [support helicopter] support is therefore unsustainable.”

In an assessment of Nato operations in Afghanistan, he concluded that the system for managing helicopter movements in the country “is very clearly not fit for purpose”. He added that helicopter operations in Iraq “were managed in a more flexible, efficient manner”.

The e-mail, classified “Nato Secret” was published in the Daily Mail after being leaked to a Conservative MP by an MoD official.

A report by another senior officer in Afghanistan, written on July 10, was also leaked. It reads: “Aviation has been erratic throughout this week. This has forced us to conduct more road moves than I would like. I understand the strains in the fly programme but any improvement would greatly assist.”

The officer says he had received only the helicopters he had asked for that week, and complained that Viking armoured vehicles were being overused because of helicopter shortages.

Adam Holloway, the former Grenadier Guards officer who received the e-mails, told the newspaper: “What a heart-wrenching irony it is that Colonel Thorneloe wrote those words.

“It must have been terrible for him as the commander of 800 men to know that their lives were being put in danger because the Government, in whose name he had taken them to war, would not spend the money to make it safer for them to move across country.”

He added that defence chiefs “should be ashamed — hopefully now they will at last do the right thing and get our troops off the roads and into the air where they are safer.”

Colonel Thorneloe, who had two young daughters with his wife Sally, said in an interview with The Times days before his death: “The mission itself is one that people do believe in.”

Soon after Colonel Thorneloe’s death, on July 22, Gordon Brown said at his monthly press conference: “In the operations we are having at the moment it is completely wrong to say that the loss of lives has been caused by the absence of helicopters.”

Yesterday Bob Ainsworth, the Defence Secretary, said: “My thoughts remain with the family and friends of Lieutenant-Colonel Rupert Thorneloe, who was a courageous soldier and a fine man. Our brave forces deserve the very best equipment and we remain determined to provide it.

“We know the value of helicopters on operations, and that commanders could do more with more. That is why we have increased the numbers and types, improved engines and almost doubled flying hours. To counter the roadside bomb threat we have also been improving unmanned air surveillance.”

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