A soldier from 2nd Battalion The Royal Welsh has died following an explosion in southern Afghanistan, the Ministry of Defence said.
The serviceman, whose next of kin have been informed, was caught in the explosion while on a vehicle patrol in the Musa Qal'eh district, of northern Helmand Province.
His death takes the total number of British service personnel who have died since the start of operations in Afghanistan in 2001 to 218.
Task Force Helmand spokesman Lieutenant Colonel Nick Richardson said: "The death of this brave soldier from 2nd Battalion The Royal Welsh is mourned by his friends, colleagues and all of us serving in Task Force Helmand.
"We know that our loss is nothing compared to the sorrow of his family, to whom we extend our deepest sympathies."
The soldier's death comes after two American servicemen were killed on Saturday.
A Nato spokesman said one died as a result of a roadside bomb and the other was killed in an insurgent attack.
French officials said three soldiers also died in a violent storm in north-eastern Afghanistan.
One soldier was struck by lightning while two were swept away by a rain-swollen river.