One source told The Daily Telegraph the number of Britons in the tribal areas of Pakistan continues to be a concern because the al-Qaeda leadership based there is a “source of terrorist planning and when Brits are involved it would seem logical to assume that the focus of such planning could be the UK.”

The latest video is designed as a recruitment video for suicide bombers and militants, featuring image after image of dead fighters, accompanied by a song glorifying their activities, that can be watched on a mobile phone . . . released in the last few days with English subtitles which identify one of the martyrs for the first time as “Musa the British.”

The video is accompanied by a nasheed [Islamic song] in urdu, suggesting it was made in Pakistan. It opens with a clip of “Yusuf al-Kuwaiti” driving himself to a suicide bomb attack in Iraq, accompanied by an imperfect English translation that reads: “Right now I am feeling such a felicity in my heart that it can’t be understood by anyone except Allah. I make duaa [supplication] to Allah to grant me steadfastness until I meet him drenched in blood.” The song, which is unaccompanied in traditional Islamic style, is translated in subtitles that read: “In our lifetime we longed for this one desire, our chests be adorned only with bullets."

Neil Doyle, an expert in extremist videos, said: “These images are of people who have laid down their lives for their religion, They de-sensitise the viewer to death and make the direct proposition: ‘What are you going to do?’”