The soldiers were killed in a roadside blast in the the Nahr-e Saraj district of Helmand province (Reuters)
British soldiers in Helmand province (Reuters)

British troops have closed their last remaining forward operating base (FOB) in Afghanistan's Helmand Province.

Observation Post Sterga was one of more than 130 such bases designed to provide a safe location for soldiers or airmen, away from the main operating bases, like Camp Bastion.

Sterga opened in August 2013 to allow UK personnel to observe a large and strategically important area of central Helmand.

Defence Secretary Philip Hammond, who was in Helmand Province to witness the closure of the base, said: "This is another important step towards ending combat operations in Afghanistan.

"It's also an opportunity to reflect on the mission and the hard work and sacrifice of British forces," he added.

"Their efforts have helped build a credible Afghan National Security Force and supported the emergence of a democratic Afghan state."

The closure of the base means British armed forces personnel are now situated only in Camp Bastion; in locations in Kandahar, which has an airbase, and in the capital, Kabul.

The move is part of the winding down of operations in Afghanistan.

A team of advisers to Afghan security forces are expected to constitute Britain's sole presence in the country by the end of the year.

A large number of the 453 British servicemen who have died in Afghanistan since 2001, were posted to an FOB at the time.