The soldier, from 36 Engineer Regiment, part of the Counter-IED Task Force, died in the incident in the Nad-e-Ali district of central Helmand Province, the Ministry of Defence said.

Spokesman for Task Force Helmand, Lieutenant Colonel David Wakefield, said: He was leading a team conducting route clearance operations at the time, making the way ahead safe for others to follow.

"His indomitable courage and fortitude, the hall-mark of his profession, will not be forgotten."

The soldier's death takes the number of British troops killed in Afghanistan to 223.

In total, 256 have died including accidents and illnesses - more than the number of British service deaths in the Falklands.

The latest death came a day after two other soldiers died in a separate explosion.

The soldiers were from The Royal Scots Borderers, 1st Battalion The Royal Regiment of Scotland, part of the 3 Rifles Battle Group.

They died while out on foot patrol, near Sangin in Helmand Province, on Sunday evening.

The soldiers were not involved in Operation Moshtarak, the new offensive being launched against the Taliban.

Lieutenant Colonel Wakefield said: "They were on a foot patrol bringing security to local people near Patrol Base Wishtan when the explosion caught them.

"Two of our comrades have been cruelly taken from us, but their bravery and fortitude will not be forgotten."

The soldiers' families have been informed.