The West is indirectly funding the insurgency in Afghanistan thanks to a system of payoffs to Taleban commanders who charge protection money to allow convoys of military supplies to reach Nato bases in the south of the country.

Contracts to supply British bases and those of other Western forces with fuel, supplies and equipment are held by multinational companies.

However, the business of moving supplies from the Pakistani port of Karachi to British, US and other military contingents in the country is largely subcontracted to local trucking companies. These must run the gauntlet of the increasingly dangerous roads south of Kabul in convoys protected by hired gunmen from Afghan security companies.

The Times has learnt that it is in the outsourcing of convoys that payoffs amounting to millions of pounds, including money from British taxpayers, are given to the Taleban.

The controversial payments were confirmed by several fuel importers, trucking and security company owners. None wanted to be identified because of the risk to their business and their lives. “We estimate that approximately 25 per cent of the money we pay for security to get the fuel in goes into the pockets of the Taleban,” said one fuel importer.

Another boss, whose company is subcontracted to supply to Western military bases, said that as much as a quarter of the value of a lorry's cargo went in paying Taleban commanders.

The scale of the supplies needed to keep the Nato military operation going is vast. The main British base at Camp Bastion in Helmand province alone requires more than a million litres of diesel and aviation fuel a week. There are more than 70,000 foreign soldiers in the country for whom food and equipment must be imported, mostly by road. The US is planning to send at least 20,000 more troops into Afghanistan next year.

Other than flying in supplies, the only overland route is through Pakistan and Taleban-controlled areas of Afghanistan.

A security company owner explained that a vast array of security companies competed for the trade along the main route south of Kabul, some of it commercial traffic and some supplying Western bases, usually charging about $1,000 (£665) a lorry. Convoys are typically of 40-50 lorries but sometimes up to 100.

Asked whether his company paid money to Taleban commanders not to attack them, he said: “Everyone is hungry, everyone needs to eat. They are attacking the convoys because they have no jobs. They easily take money not to attack.” He said that until about 14 months ago, security companies had been able to protect convoys without paying. But since then, the attacks had become too severe not to pay groups controlling the route. Attacks on the Kandahar road have been an almost daily occurrence this year. On June 24 a 50-truck convoy of supplies was destroyed. Seven drivers were beheaded by the roadside. The situation now was so extreme that a rival company, working south of the city of Ghazni, had Taleban fighters to escort their convoys.

“I won't name the company, but they are from the Panjshir Valley [in north Afghanistan]. But they have a very good relation with the Taleban. The Taleban come and move with the convoy. They sit in the front vehicle of the convoy to ensure security,” said the company chief.

The Taleban are not the only ones making money from the trade; warlords, thieves, policemen and government officials are also taking a cut.

A transport company owner who runs convoys south on the notoriously dangerous Kabul to Kandahar highway said: “We pay taxes to both thieves and the Taleban to get our trucks through Ghazni province and there are several ways of paying. This goes to a very high level in the Afghan Government.

“Mostly the [Afghan] security companies have middlemen to negotiate the passage of the convoys, so they don't get attacked. They pay on a convoy by convoy basis to let the convoy pass at a certain time. They have to pay each of the Taleban commanders who control each part of the road. When you hear of an attack it is usually because a new small [Taleban] group has arrived on the road.”

Lieutenant-Commander James Gater, a spokesman for Nato forces in Afghanistan, said that the transport of Nato supplies was contracted to commercial firms and how they got them into the country was their business.

“I can confirm that we use two European-headquartered companies to supply food and fuel, though for contractual reasons it is not prudent for us to name them. They provide their own security as part of that contract. Such companies are free to subcontract to whomsoever they wish.

“We are aware they do prefer to subcontract from the countries in which they are operating. In Pakistan they prefer to use Pakistani trucking companies, in Afghanistan they prefer Afghan trucking companies. That is a commercial decision for them.”

A representative for the Swiss-based Supreme Global Solutions confirmed that the company held supply contracts with the military in Afghanistan.

However, last night the company denied paying protection money. “We categorically reject any suggestion that we now, or have ever, paid money to any individual for the safe passage of our convoys. Furthermore, we do not permit our subcontractors to do so on our behalf,” it said.

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