In the diplomatic cable written by François Fitou, the deputy French ambassador, Sir Sherard Cowper-Coles is also quoted as saying that the coalition's military presence is "part of the problem not the solution".
Sir Sherard is quoted as saying that the American strategy in Afghanistan 'is bound to fail'
In the cable, dated Sept 2 and published in the investigative and satirical weekly Le Canard Enchaîne, Sir Sherard is quoted as having said that "the current situation is bad. Security is worsening, but also corruption, and the current government has lost all credit."
He is alleged to have gone on to say that "the presence, notably military, of the coalition is a part of the problem, not the solution.
"Foreign forces are assuring the survival of a regime, which, without them, would quickly crumble. In doing so, they are slowing down and complicating an eventual end to the crisis (incidentally, probably a dramatic one)."
France has just agreed to increase its deployment in Afghanistan despite public resistance, and send more drones and helicopters.
In other quotes from the coded cable, addressed to President Nicolas Sarkozy and Bernard Kouchner, the foreign minister, the British ambassador is cited as saying that sending extra French troops "would have perverse effects: it would single us out even more clearly as an occupying force and multiply the number of targets (for insurgents)."
He is quoted as saying that the only solution at present is to support the Americans "but we must tell them that we want to be part of a winning, not a losing strategy."
According to the newspaper, Sir Sherard said that the best scenario was that "in five to ten years," when British troops were no longer present on Afghan soil, the country would be "governed by an acceptable dictator".
"This is the only realistic outcome, and we must prepare public opinion to accept it ... In the meantime, the American presidential candidates must be dissuaded from getting further bogged down in Afghanistan. (Their) strategy is bound to fail," he reportedly said.
However, a British embassy spokesman said the views were not the Ambassador's.
"It is not for us to comment on something that is presented as a French telegram, but the views quoted are not an accurate representation of the Ambassador's views.
"The UK, with international partners, is committed to working in support of the government of Afghanistan to deliver solutions to the challenges facing the country, through both civilian and military effort.
"The UK has always acknowledged that success in Afghanistan is a long-term objective, and requires a comprehensive approach to address security, political, social and economic development.
"The UK and the US are united in the Afghanistan strategy. We work closely with our US allies in all aspects of decision making and regularly review our approach.
The Foreign Office said yesterday that Britain had decided to withdraw the 60 children of diplomats based in neighbouring Pakistan in the wake of the bombing at the Marriott Hotel in Islamabad last month. A spokesman said that spouses would also be offered the opportunity to leave.
While the review was triggered by the terrorist incident, it reflects the growing instability of the country and reflected the broad views of diplomats. Officials said the ruling will be lifted as soon as conditions permit.
Speculation was mounting that one of the suspects in the hotel bombing, the leader of the Pakistani Taliban, had died of kidney failure. Baitullah Mehsud, who is in his mid-30s is also accused of being responsible for the assassination of the former prime minister, Benazir Bhutto, was known to have been unwell for months.
A doctor who has treated him insisted that Mehsud had a kidney problem but was still alive. But if the rumours prove to be true his death would prove a triumph in anti-terrorist efforts by Pakistan and the West.