A full-scale manhunt involving British special forces and Afghan police units is under way in Helmand to try to find the gunman responsible for shooting dead five soldiers in Nad-e Ali.

Tributes to the soldiers murdered by an Afghan police officer poured in yesterday as the death of another British serviceman was announced.

An sas squad was last night leading the manhunt for the Afghan assassin who gunned down five British soldiers in cold blood.

The killer has been identified only as a policeman called Gulbuddin.

It was unclear last night whether he was simply a lone rogue officer or a Taliban infiltrator acting with an accomplice.

The Royal Military Police are investigating whether the gunman, identified as Gulbuddin, was acting alone in response to a “ticking off” he received from one of the British military mentors reportedly Warrant Officer 1 Chant, or that he was a Taleban infiltrator who picked his moment when the British troops were most vulnerable.