Camberely: Britain's Prince Harry, once dubbed a royal wild child for underage drink and drug antics, graduated as an army officer yesterday before joining a regiment that could be sent to Iraq or Afghanistan.

The third in the line to the throne passed out at the elite Sandhurst military academy before his grandmother, Queen Elizabeth, at a colourful ceremony rich in military tradition.

A sombre-faced Harry marched with sword in hand across the parade ground to start his military career and stood to attention, back ramrod straight and eyes to the front, as his grandmother inspected the cadets. Officer Cadet Wales now becomes a Second Lieutenant in the Household Cavalry and will train to become a troop commander in charge of 11 men and four light tanks in an armed reconnaissance unit. That could mean his serving in conflict zones.

Harry, whose mother Princess Diana died in a Paris car crash when he was just 12 years old, has insisted he wants a frontline role in the British Army.

"There is no way I am going to put myself through Sandhurst and then sit on my a*** back home while my boys are out fighting for their country," he said in an interview to mark his 21st birthday last September.

"That may sound very patriotic but it's true," added the red-haired prince whose elder brother William is also training at Sandhurst to become an army officer.

Despite the best efforts of courtiers to groom his image, Harry has more often than not hit the headlines for the wrong reasons.

He dabbled in marijuana and under-age drinking as a 17-year-old. In response, his father Prince Charles sent him to a drug rehabilitation clinic in London for a day to give him a glimpse of the dangers of drug abuse. Since then, Harry has scuffled with paparazzi outside a London club and sparked outrage by dressing as a Nazi officer at a party. He apologised afterwards for the offence he caused.

His girlfriend Chelsy Davy was due to fly in from Cape Town to attend a Sandhurst ball last night but she may have some frosty words for Harry and fellow cadets were said to have celebrated graduation last week by visiting a strip club.

Britain's Royal Family has a long tradition of serving in the armed forces and Harry's Uncle, Prince Andrew, was a helicopter pilot in the 1982 Falklands War against Argentina.

The Household Cavalry, made up of the Life Guards and the Blues and Royals, offers some intriguing royal connections.

Andrew Parker Bowles, who served with the Blues and Royals, was known as Britain's most famous cuckold when his wife Camilla was the mistress of heir to the throne Charles. Camilla and Charles finally married last year after a 35-year romance. And James Hewitt, who had an affair with Harry's mother Diana, spent 17 years with the Life Guards and saw action during the first Gulf War.