The soldier, from the 1st Battalion The Royal Anglian Regiment, died after a blast during a patrol in the outskirts of Sangin in the volatile Helmand province.

Two other casualties are being treated in hospital for injuries which are not thought to be life threatening, the MoD said.

He was the 65th British forces personnel to die in Afghanistan since the start of military operations there in November 2001 and the first to be killed while travelling in the army's new "Vector" protected patrol vehicle.

The explosion happened at around 5.50am local time (2.20am BST) in the north eastern outskirts of Sangin, as the soldiers were returning to base after a routine patrol, an MoD spokesman said.

The soldier who died was airlifted to hospital at Britain's Camp Bastion base but did not survive.

His two injured comrades were also taken for medical treatment.

The MoD said that because the damaged vehicle could not be removed it had to be destroyed to stop it falling into Taliban hands. The convoy then continued to its destination.

A spokesman said that the three soldiers' next of kin had been informed and had asked for at least 24 hours before any further information is released.

Vector, which is more suitable for rugged terrain than the army's existing "Snatch" patrol vehicle, was recently introduced as part of a package of measures designed to increase troops' safety in Iraq and Afghanistan. The first Vectors began arriving in the country in April of this year and are being phased in, set to replace most of the Snatch vehicles by late October.