The 24-year-old third-in-line to the British throne has flunked the theory-based flying test at a Royal Air Force base in Lincolnshire only few weeks into his two-year course, the 'News of the World' reported.

"Harry didn't reach the grade but he will have plenty of other opportunities to pass it. He will now be given extra tuition. It wasn't a case of Harry failing and being booted off the course. It's part of an on-going assessment," a Royal source was quoted by the British tabloid as saying.

Prince Harry, an Army Lieutenant in the Household Cavalry's Blues and Royals, is currently on an attachment to the Army Air Corps for his flying training.

In January, Harry had apologised for calling one of this army colleagues a "Paki", a derogatory term for Indians and Pakistanis. He had made the remark in 2006 at an airport departure lounge as soldiers waited to travel to Cyprus for training exercises.

"Harry was making a film of his army mates using a camcorder. He was talking over it -- moving the shots to different individuals.

"But when he passed over an Asian- looking soldier, he stopped and zoomed in. Then he said, 'And here is our Paki friend' -- before moving on to someone else," a senior Royal source had said.