A soldier from 1st Battalion Grenadier Guards has been killed in Afghanistan while on sentry duty, the Ministry of Defence said on Saturday.
The soldier was serving in the Nahr-e Saraj district of Helmand Province when he was killed by "enemy action" on Friday.
Next of kin have been informed and asked for a 24-hour period before further details are released.
Major Ian Lawrence, spokesman for Task Force Helmand, said: "It is with great sadness I must inform you that a soldier from 1st Battalion Grenadier Guards has been killed whilst on sentry duty in the Nahr-e Saraj district of Helmand Province.
"The thoughts and prayers of everyone in the Task Force are with his family and friends at this very difficult time."
The soldier's death brings the number of members of UK forces to have died since operations in Afghanistan began in October 2001 to 425.