Harry is understood to be considering a military career

The move has already fuelled speculation that the 18-year-old, who is third in line to the British throne, may opt for a military career.

Harry was parade commander for the annual tattoo of the school's Combined Cadet Force.

The Prince of Wales was among those looking on as his youngest son led the guard of honour's march out on to College Field with their colours.

Former Royal nanny Tiggy Pettifer was also among the 500 or so friends and families watching the evening parade.

Barking orders, Harry led the boys out to be inspected by Old Etonian Brigadier Jamie Balfour, former Commander of the British Armed Forces in Bosnia and now Director of Infantry.

Harry's parade in pictures

BBC correspondent Nicholas Witchell, watching the parade, said: "It all went very smoothly, he seemed to do a good job.

"And of course it begs the question whether he is thinking about a career in the armed services.

"It would be in his family's mind that life in the army possibly would give his life the structure and the discipline which perhaps would be important for him.

"There is little doubt that he is thinking about the possibility of joining the army but officials stress he hasn't done his A-levels yet, he doesn't leave Eton until later this summer, and no decision about what he does then has been taken."

Mock battle

The Cadet Corps, founded in 1860, is voluntary at Eton but only open to the sixth form. There are currently 140 members.

As well as the parade and inspection, this year's hour-long tattoo included a gun race, a demonstration of unarmed combat and military music.

Life in the army possibly would give his life the structure and the discipline which perhaps would be important for him The BBC's Nicholas Witchell

The finale was a staged pitched battle between the Eton Rifles and "evil paramilitary" forces - of which Harry was one - over control of a mock castle.

The evening ended with awards, an address by Brigadier Balfour and finally the National Anthem.

Prince Harry, who has experimented with drink and drugs, has also earned a reputation as an excellent sportsman.

Several newspapers have reported recently that both Harry and his elder brother William are to continue the royal tradition of service in the armed forces.

Their father and the Duke of York were both in the Royal Navy. The Earl of Wessex left the Royal Marines after training.