In total, 217 UK personnel have now died in Afghanistan since 2001
A British soldier has been killed in an explosion while on patrol in Helmand province, southern Afghanistan, the Ministry of Defence said.
He was from 2nd Battalion the Mercian Regiment. Next of kin have been told.
Lt Col Nick Richardson, spokesman for Task Force Helmand, said he had been a "courageous soldier" and extended his sympathies to the man's family.
The death takes the number of UK troops killed in Afghanistan since the start of operations in October 2001 to 217.
The unnamed soldier died in the Gereshk district on Monday morning.
Lt Col Richardson said: "The death of this courageous soldier from 2nd Battalion the Mercian Regiment is a heartfelt blow to all of us serving in Task Force Helmand.
"Our sorrow is nothing compared to the heartache felt by his family to whom we extend our deepest sympathies."