Harry brawls while Wills drools

But while both are renowned for their exceptional thirst, large quantities of alcohol seem to affect them in radically different ways - as their latest escapades show.

Wills, 24, becomes an affable drunk, happy to dance with strangers and unconcerned at their tendency to take pictures of him with their mobile phones.

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Harry, 22, turns into Prince Pugnacious - ever ready to take a swing at the paparazzi who have an unfortunate knack of catching him at his most undignified.

His latest clash with the cameramen happened in the early hours of Saturday as he emerged from his regular haunt, the London nightclub Boujis.

Instead of heading straight to his chauffeur- driven Range Rover, he swore and lunged at a photographer before losing his balance and tumbling into the gutter.

Before his latest fall from grace, Harry had been downing Crack Baby cocktails - a heady mix of vodka, passion fruit, raspberry liqueur and champagne - with his friend and budding TV presenter Natalie Pinkham. Delivered in a test tube, the Crack Baby is designed to be 'downed in one' and costs £8 a time.

A bottle of vodka - which also ensures drinkers a table at Boujis - costs £250 and comes with a variety of juices and soft drinks so that customers can mix their own cocktails.

However Harry and his brother tend to drink on the house because manager Jake Parkinson-Smith is grateful for the publicity that their visits ensure.

It is not clear quite how many Crack Babies Harry dispatched, but he was seen dancing suggestively with 29-year-old Miss Pinkham. That will not go down well with his girlfriend Chelsy Davy, particularly since the prince has previously been photographed fondling Miss Pinkham intimately at another club.

The fracas broke out when Miss Pinkham left Boujis via the main entrance at 3am and Harry tried to slip out of the back - but ran straight into a posse of photographers, including Nirach Tanner.

"He was very drunk,' said Mr Tanner, 27. "I took a few shots and he just came for me. He knows me because I've taken his pictures before and I have never had a problem with him.

"He screamed at me to "f*** off" then grabbed me and tried to shove me over. He had his hands around my collar and back. It was an assault."

Harry then apparently thought better of attacking Mr Tanner and tried to get into the Range Rover.

Unfortunately he turned too sharply and fell into the gutter, displaying his pink socks and boxer shorts to the assembled throng.

"His bodyguard had to help him up and direct him into the car," said another witness. "Harry looked a bit dazed and buried his head in his arms," another witness said.

The prince, who is due to be sent to Iraq in May with the Blues and Royals, has another week of pre-deployment training before he is given three weeks leave. Friends say he hopes to spend much of this time with Zimbabwean Chelsy, who is currently touring the world on a gap year from university.

A Clarence House spokesman insisted that the Boujis incident had been "taken out of context".

"The prince was on a night out with 15 friends after spending a week on exercise with his Army regiment. As he left the nightclub he started joking around with one of the photographers but unfortunately lost his footing and stumbled"

Despite the excuses, royal sources say that Harry's behaviour is a worry. "No one has a problem with him letting his hair down every now and again, especially as he is about to go and fight in Iraq," said one.

"The fact that he acts like any young lad of his age is one of the most endearing things about him.

"But there is growing concern that Harry is starting to get himself a reputation as a 'waster'. He is seen as the spare to William's heir. As a result, he gets far more leeway than his elder brother.

"The feeling is, however, that unless he uses that freedom wisely, he will be seen as nothing more than a playboy prince dabbling at war games because he has nothing better to do with his life. That would be incredibly unfair on him, of course, but he needs to start watching his back."

One hundred miles away in Bournemouth, William was spotted downing shots of sambuca and gyrating on a podium in the Elements nightclub.

His girlfriend Kate Middleton might raise an eyebrow to hear that he invited a 6ft blonde student back to his barracks at Bovington.

Lisa Agar, 19, and a male friend had drinks with the prince in the officers' mess but left at 4.15am when William nodded off in his chair.

Miss Agar said that he failed to mention Miss Middleton once as he invited her to dance to hits including the Baywatch theme tune at the club.

"He was quite affectionate and touchy-feely. And he definitely wasn't a shy boy."

To complete the royal revelry, the princes' cousins Beatrice and Eugenie were snapped emerging from the London nightspot the Cuckoo Club in the early hours of Sunday.

The York girls were escorted by Beatrice's boyfriend, American marketing man Dave Clark, who is six years her senior.

The club might be asked to explain why schoolgirl Eugenie, who celebrated her 17th birthday last week, was allowed to party there until well after 2am.

The way in which she shielded her face from photographers suggests that the teenager, who is studying for A-levels at Marlborough College, might have realised she was in trouble too.