And when short-term needs arise, such as the evacuation of British citizens from Lebanon last month, the armed services have to meet them.

ECONOMIST: The armed forces

Mr Ball joined the armed services at 15 and spent 10 years in the Royal Navy before starting work for British Coal in 1964.

BBC: Asbestos fibres

As well as attending the prizegiving dinner at the Atlantic Council, Prince Harry is also expected to meet British and American athletes who have taken part in the Warrior Games, a paralympic sports tournament for armed services personnel, in Colorado.

CNN: Prince Harry to visit U.S. to receive humanitarian award