Karzai said he "saw no good" in the American presence in his country.
"They did not work for me, they worked against me," he said, and referred to the Taliban as "brothers" and the Americans as "rivals". He was slightly more generous in his assessment of Britain, "which has conducted with us in a very civilised way and tried to bring better relations between us and Pakistan".
But he added a damning assessment of the British role leading security forces in the southern province of Helmand, saying it had been flawed: "In general the US-led Nato mission in terms of bringing security has not been successful, particularly in Helmand."
His rhetoric has been badly received in Washington, where politicians are ever more infuriated by Karzai's stance.
America spent US$648 billion during the war, which has cost 2211 US lives. Last week Congress cut development aid to Afghanistan in half, reducing it to US$1.1 billion. But Karzai is unrepentant.
"The money they should have paid to the police they paid to private security firms and creating militias who caused lawlessness, corruption and highway robbery," he told the Sunday Times. "They then began systematically waging psychological warfare on our people, encouraging our money to go out of our country. What they did was create pockets of wealth and a vast countryside of deprivation and anger."
There is no front-runner to succeed Karzai.