Prince Harry has started a tough Army selection process to become a helicopter pilot, Clarence House said today.

The royal will be "graded" next month to determine whether he can start the full Army Air Corps programme.

Candidates take a four-week course to chalk up 13 hours of flying when they need to prove their ability to learn and progress.

Sources said the failure rate is high - around half the soldiers who take the course do not make the grade. If Harry succeeds, he will follow in the footsteps of a number of royals, including his brother William, who trained in a helicopter with the RAF.

Prince Harry has passed an initial aptitude test and if he successfully completes the four-week course will progress to full flight training in January. This takes 16 months. Harry could fly one of three different types of helicopter if he succeeds; a Gazelle, Lynx or Apache.

The prince has already served two-and-a-half years in the Household Cavalry Regiment. He spent 10 weeks in active service in Afghanistan from December last year. The MoD would not comment if Harry would be likely to serve in a war zone as a pilot.