The government said the soldier -- the 445th British serviceman to be killed in Afghanistan since the US-led invasion in 2001 -- had been killed by enemy fire while on patrol in the restive southern Helmand Province.
"Despite receiving immediate medical attention, he died from his injuries at the scene," the ministry said in a statement, adding that the soldier's family have been informed.
Britain currently has around 8,000 military personnel in Afghanistan, but just 5,200 will be left by the end of the year ahead of a full withdrawal by the end of 2014.
British troops have been based in Afghanistan’s southern Helmand province since the US-led war in Afghanistan began. Some nine-thousand troops are currently stationed in the war-ravaged country.
The increasing number of military casualties in Afghanistan has caused widespread anger in the US and other NATO member states, undermining public support for the Afghan war.
The US-led war in Afghanistan removed the Taliban from power, but insecurity continues to rise across Afghanistan, despite the presence of thousands of US-led troops.
NJF/NJF