The murder of five British soldiers inside a compound shared with Afghan National Police officers last night has caused shockwaves throughout Britain’s Task Force in Helmand province.

It’s the worst single incident involving a hostile attack against British troops since they were first deployed to Helmand in the spring of 2006 and brings the total number of fatalities since 2001 to 229.

If the “rogue” Afghan policeman responsible for the shooting turns out to have been recruited by the Taleban it will undermine the whole strategy of partnership between the British and Afghan security forces - the key element of the campaign in Helmand.

The death of three soldiers from the Grenadier Guards and two from the Royal Military Police in Nad e-Ali in central Helmand - and the escape of the gunman - raises suspicions that the British personnel may have been unarmed when the attack occurred. It seems unlikely that the soldiers would not have returned fire when the shooting started.

The soldiers were in a compound next to an Afghan police checkpoint. The British soldiers live with the Afghans and mentor their checkpoint skills. It’s part of the training programme which Britain and her Nato allies hope will eventually make it possible for the Afghan National Army and Afghan National Police to take over responsibility for security in Afghanistan.

The Royal Military Police special investigation branch which launched an inquiry last night will be focusing on two possible explanations for the shooting: either the Afghan police officer was involved in a tribal dispute which boiled over or he was a Taleban plant under instructions to kill British soldiers. Defence sources said the Afghan was a genuine police officer and had been known to the British soldiers for some time.

Tribal disputes are not uncommon and it may be that he was unhappy serving in Nad e-Ali. But the area has a strong Taleban presence, and the Royal Military Police will be investigating any evidence that the gunman might have deliberately planned the killings under Taleban instruction.

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