"According to our information, the likelihood is that all the Afghans we handed over were tortured," Colvin said. "For interrogators in Kandahar, it was standard operating procedure."

Colvin said Canada took roughly six times more prisoners than British forces and 20 times more than the Dutch. He said the vast majority of them were not "high-value targets" such as Taliban commanders, Al-Qaida operatives or bomb-makers, but rather ordinary Afghans, many with no connection to the insurgency.

He said some of them may have occasionally carried a gun for the Taliban, either having been bought or coerced, he said, but many were farmers, truck drivers and peasants "in the wrong place at the wrong time.

"Some of our actions in Kandahar, including complicity in torture, turned some local people against us. Instead of winning hearts and minds we caused Kandaharis to fear the foreigners," he said. "Canada's detainee practices, in my view, alienated us from the population and strengthened the insurgency."

Peter Kent, Canada's parliamentary secretary for foreign affairs, said since a new transfer agreement was signed with Afghan officials, the Canadian government has received no complaints of torture.

Transfers were suspended for a short time in 2007 after Canadian officials saw evidence that one prisoner was abused by his Afghan jailer after being handed over.