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Britain’s last chance of securing this treacherous corner of Afghanistan lies in the hands of a piratical, black-turbaned figure with long beard, white cloak and silver-sequinned slippers with curled toes.

Mullah Abdul Salaam may not look much like a white knight. He served as a commander in the Taleban and even today his true loyalties remain suspect. The 45-year-old former Mujahidin guerrilla could, however, decide the fate of the British mission to stabilise the lawless province of Helmand, where this week he was put in charge of the key district of Musa Qala.

“He’s not just the best show in town,” one British officer remarked. “He’s the only show in town.”

Mullah Salaam’s rise to power in Musa Qala, the test case for British efforts to evict the Taleban and install central authority, is a classic Afghan tale of intrigue, bloodshed, farce and fate. In an interview with The Times the former warlord explained how last year he had severed relations with the Taleban, was courted secretly by a foreign diplomat and eventually swapped sides to join the British-led effort.

“The Taleban called a shurah [council] to attack the district centre and coalition forces there but though invited I did not attend nor fight,” he said. “It was not a good thing.”

He was then approached by Michael Semple, an Irish diplomat working for the European Union in Kabul. Mr Semple, a fluent Pashto-speaking veteran of Afghanistan, was expelled last month by the Government in Kabul for his back-channel contacts with the Taleban.

Before being ordered out he managed to put together a deal with the former Taleban commander. “We discussed reconciliation and unity in Afghanistan,” Mullah Salaam said of the first of his several meetings with Mr Semple. “I was surprised to hear of his recent expulsion.”

Mullah Salaam went to Kabul for a meeting with President Karzai last autumn. He caught the Afghan leader’s imagination with the promise of a tribal uprising against the Taleban, which could, potentially, deliver Musa Qala into government hands with barely a shot being fired. The idea led to a War Cabinet meeting in Kabul, which included the British and American ambassadors, President Karzai and General Dan McNeill, the commander of Nato forces in Afghanistan.

The result was operation Mar Karadad, which had to be accelerated at the end of November when Kabul heard news that Mullah Salaam, now back in Musa Qala, had attracted the attention of the Taleban and the uprising was imminent.

There was no uprising. When Afghan, British and US units closed in on Musa Qala last month, Mullah Salaam stayed in his compound in Shakahraz, ten miles east, with a small cortège of fighters, where he made increasingly desperate pleas for help.

“He said that he would bring all the tribes with him but they never materialised,” recalled one British officer at the forefront of the operation. “Instead, all that happened was a series of increasingly fraught and frantic calls from him for help to Karzai.”