"We had someone there who witnessed it," said Ali Aqbar Turi, a local Shia leader, as we examined the evidence in Peshawar. "They were alive as it was done. A father and son were among the victims. They started with the arms, then the legs and heads, and said things like ‘Huh, how do you like the taste of that?' as they did it. There were people standing around filming it." Wrestling with a momentary wave of nausea in the airless room, I saw nothing in the images to dispute his claims. Piled together were eight torsos, eight severed heads, eight pairs of legs and arms. Some of the faces had been mutilated, but all were identifiable. The wounds seemed surgical, so precise they could have been the work of a butcher.

In another Taliban video, this time shot in Waziristan, I saw four boys who looked too young even to be teenagers stand behind a captured Pakistani NCO, Lance-Corporal Hussain. Three carried Kalashnikovs, one brandished a knife. All had koranic inscriptions wrapped around their foreheads. They pushed the captive soldier to the ground and sawed off his head. One boy then held it up to the camera. Next they turned in file and marched away.

Worst of all, they were expressionless throughout.

Terror has become both means and ends in Fata. In suicide bombings the militants believe they have found a strategic weapon to take on the state, while beheadings are a successful tactic in terrorising the local Fata population into submission. Some 200 maliks have been executed by the Taliban in Fata since 2004, along with an unknown number of minor officials, alleged government collaborators and Nato spies, teachers and tribesmen unwilling to submit to the Taliban.

In a typical example told to me by a resident from the Mohmand agency, who like so many witnesses I spoke to was too frightened to be named, the Taliban tried to arrest "Yusuf", the leader of an armed group of non-aligned tribesmen, in a village there in the autumn of 2007. There was a shoot-out and three Taliban were killed. Yusuf and his group fled their village and were pursued. They were surrounded and six shot dead, including Yusuf. Another eight were captured. The next day the Taliban summoned 4,000 men from the district to attend the funeral prayers for their own dead at Yusuf's village. The eight prisoners were beheaded before the crowd. The bodies were left in the open for three days before relatives were allowed to bury them.