London - A British commander of reservist Special Air Service (SAS) troops in Afghanistan has resigned in protest over what he has called the "chronic underinvestment" in protective military equipment for use in Afghanistan, the Daily Telegraph reported on Saturday.

Major Sebastian Morley in his resignation letter singled out the continued use of the so-called Snatch Land Rover vehicles commonly used in Afghanistan to transport troops, which have been criticized for their lack of sufficient armour.

Morely's resignation comes after the deaths of four soldiers in Helmand province in June, which the Major says could have been prevented had better-armoured vehicles been available.

Corporal Sarah Bryant ­ the first female soldier to die in Afghanistan - and three male colleagues, SAS soldiers Corporal Sean Reeve, Lance-Corporal Richard Larkin and Paul Stout were killed when their Snatch Land Rover struck a roadside bomb.

The lightly-armoured Snatch was originally developed for use against rioters in Northern Ireland - dubbed Snatch as it was frequently used to make arrests. In Iraq and Afghanistan it has become known as the "mobile coffin."

The Telegraph reported that the poor armour of Snatch vehicles has been responsible for the deaths of 34 soldiers in Iraq and Afghanistan. 121 British soldiers have been killed in Afghanistan since 2001, and 500 injured.

A 700-million-pound (1.13-billion-dollar) Ministry of Defence (MoD) programme to replace the Snatch vehicles is now underway.

The ministry has been accused by soldiers serving in Iraq and Afghanistan of negligence in equipping its troops.

A MoD spokesman said: "Equipping our personnel is a clear priority and we are absolutely focused on providing them with a range of vehicles that will protect them from the ever-shifting threats posed by the enemy." (dpa)