Prince Harry will return to Afghanistan after qualifying on Wednesday as a front-line Apache attack helicopter pilot.

The 27-year-old, who spent 10 weeks as an infantry soldier in Helmand in 2008, will join a unit which has the highest "kill rate" of any serving in Afghanistan.

Royal sources said he was looking forward to "doing his duty" after completing a gruelling 18-month training programme that culminated in his finishing top of his class and being declared "limited combat-ready" yesterday.

With his brother, Prince William, currently serving as an RAF search and rescue pilot, the prince's forthcoming deployment means two members of the British royal family will be on operational service for the first time since the modern armed forces were formed.

In a marked departure from the media blackout agreed during his previous tour of Helmand, the British ministry of defence made it clear in an announcement on Wednesday night that Prince Harry will be expected to fly in combat.

The ministry decided no blackout was necessary this time because the prince will be far less vulnerable as a pilot than he was when he went on foot patrols four years ago. In his role as co-pilot gunner in a two-man crew, h e will operate the aircraft's weapon systems, which include Hellfire missiles and a 30mm chain gun .