2nd Lt Gordon Sweny of 42 Commando greets a nomad

The 150 commandos from 42 Commando based at Bickleigh near Plymouth, have been in the southern Helmand province preparing for 3,500 UK troops.

They provided security while a large camp and airstrip was built at Lashkar Gar, the capital of southern Helmand.

The marines, who left England in mid-February, said it was a successful mission in one of the country's most violent and lawless provinces.

Two weeks ago, three British soldiers were injured when a vehicle carrying explosives was driven by a suicide bomber into a military convoy close to the base's entrance.

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The marines have now handed over responsibility for the force protection task to 16 Air Assault Brigade.

Major Steve Lee, Commanding Officer of J Company, said: "It is a dangerous place.

"But we are very professional, well armed and equipped and we go about our business in a highly appropriate and mature manner.

Troops from 42 Commando at Bickleigh on patrol in Helmand

"We maintained safety. The insurgents, warlords and drugs traffickers all in the main kept away from us and my guys worked a very successful routine."

The UK already has 2,000 troops in Afghanistan and 3,500 extra troops are expected to be based at the new site in Lashkar Gar for the next three years.

The new British deployment is part of an expanded Nato force in southern Afghanistan and replaces a much smaller American force which is hunting the Taleban.

Their task will be to enforce security and support the government in the area which is a centre of Taleban support and opium poppy growing.

The marines who have returned home to Devon will now go on leave until they resume training as Britain's sea-borne fast response unit.