'SAS' & US Marines In Firefight With Taliban - Video
Footage uploaded to Youtube purports to show members of the SAS fighting alongside United States Marines in Afghanistan. (video embedded below)
note: while it's apparent that the soldiers in the footage sporting British accents and kit are with UK forces, it's also possible they are members of an elite recce unit such as the Pathfinder Platoon (16 Air Assault Brigade).
Link to original video: