Leak reveals West's distrust of Alliance

The British and US governments are rethinking strategy for a post-Taliban Afghanistan in the light of a secret Whitehall analysis depicting the Northern Alliance as deeply divided, incapable of providing a stable government, ethnically biased, and devoid of credible political leadership.

The new – and ruthless – dissection of the Northern Alliance's strengths and weaknesses is clearly based on post-11 September intelligence reports and will strengthen arguments in London and Washington in favour of an international protectorate, perhaps under UN auspices, when the Taliban are defeated.

The assessment is positive about the alliance's military gains, estimating that it has doubled from 10 to 20 per cent the territory it controlled before 11 September. But while the problems it pinpoints are primarily political, it warns that the leader of one prominent mujahedin faction in the alliance would defect to the Taliban rather than fight alongside US troops.

The conclusions will nevertheless also strengthen the case for Western ground forces to enter Afghanistan, not least in order to prevent the alliance's rival components fighting against each other after a Taliban defeat, as many of the same factions did with catastrophic results after the Russians pulled out in 1992.

The report says that despite being militarily less well equipped than the Taliban, the dozen or so factions within the alliance – properly the National Islamic Front for the Salvation of Afghanistan – have been injected with a new sense of purpose since the assassination of their most charismatic military leader Ahmad Shah Masood on 9 September. It also benefits from external support from India, Iran, Russia, Turkey and the central Asian republics.

The latest intelligence is that there have been "hundreds" of defections from the Taliban to alliance forces before and after 11 September, many of them concentrated in the area round Laghman in the north-east of the country, where there has been considerable unrest. In Kapisa local citizens signed a petition to Mullah Omar calling for the expulsion of Osama bin Laden

But the alliance is riven by rivalry for the medium-term succession to Masood. At present the role is filled by General Fahim of Jamiat-I-Islami, but he faces the handicap of at least one contender within his own ranks and the fact that, as a Tajik, he is unacceptable as a future Afghan leader to Uzbekistan. There are also severe differences over the level of acceptable involvement by Western forces.

Part of the purpose of the leak appears to be to counter the assumption that the defeat of the Taliban can somehow be left to the Northern Alliance once the bombing is completed. It may also help to explain – and bolster – Tony Blair's pledge that the Western powers will not "walk away" from a role in the future of Afghanistan by allowing the Northern Alliance free rein.