Taleban chief's son-in-law one of secret envoys at peace talks

Two Afghan sources familiar with the talks, and a senior western official in Kabul this week said Motasim Agha Jan was one of three emissaries sent to the Gulf make contact with the Americans.

Diplomats insist the discussions in Qatar and at least one meeting in Germany are just "talks about talks". British sources say they are still not sure if the men speak for Mullah Mohammad Omar, the spiritual leader of the Taleban and the only man with enough authority to deliver a meaningful ceasefire.

Two former Taleban ambassadors said Mullah Omar had given the mission his personal blessing and they identified a second delegate at the talks, Taib Agha, as a close aide to the insurgent leader. The presence of Mr Agha Jan, who is married to one of Mullah Omar's daughters, also appears to corroborate claims of the leader's endorsement. A long-time confidant of Mullah Omar, Mr Agha Jan was appointed to the head of the Taleban's political commission in 2008, and would have been in charge of prospective contacts with western governments and Kabul.

There were similar exploratory meetings hosted by Saudi Arabia in 2008, but the Taleban's appetite for discussion evaporated when US President Barack Obama ordered a troop surge the following year.

Thomas Ruttig, of the Kabul-based Afghan Analysts Network, said: "Dissenting voices, ie: those who wanted an end to the bloodshed, became silent again. Ranks closed around the party line - no talks before all foreign troops have left."

A recently reconciled Taleban commander said that attitude had mellowed with the US's recent announcement of a withdrawal of troops.

Mr Agha Jan's presence in Qatar may also reveal something of Pakistan's hidden hand in efforts to end the decade-long war. The former Taleban finance minister, now thought to rank around seventh on the insurgents' leadership council, was arrested in Pakistan last year. It is not clear when, or why he was released, or how he got out of Pakistan for the talks.

Local media reports said he was detained in Karachi, in February 2010, as part of a series of raids which also captured the Taleban's second-in-command, Abdul Ghani Baradar. At the time, Afghan and western officials accused Pakistan of deliberately targeting the men in a bid to derail negotiations it felt frozen out of. Mullah Baradar and Mr Agha Jan were among the Taleban leaders thought most amenable to talks.

The current round of talks, launched in early 2011, have made little progress so far, but a senior western official said their aim was to get representatives of the Taleban to attend an international conference in Germany by December. US defence secretary Robert Gates said the talks were "very preliminary" but he hoped there would be "substantive headway" by the winter.

The Bonn Conference 2011 will resonate in Afghanistan because is ten years since an earlier conference in the same city installed President Hamid Karzai as Afghanistan's interim leader and settled on an Afghan constitution.

"The big mistake first time round was that the Taleban were left out. The Americans didn't want them at Bonn," said a western analyst in Kabul. "They don't want to make that mistake again."

Gulbuddin Hekmatyar, a former Afghan prime minister was also left out of Bonn 2001, and he now leads the third largest insurgent group battling Afghan and Nato forces.

"The Germans want everyone to come as part of one Afghan delegation," said the senior western official.

"If they come as a separate delegation then the Northern Alliance [Karzai's political opposition] will demand their own delegation."