A fracas outside a nightclub at 3am is just the lastest in a series of incidents which have painted Prince Harry as the bad boy of the monarchy. Nick Morrison asks if the third in line to the throne is heading for trouble.

ONCE upon a time there were two royal siblings. They were very close and went out of their way to look after each other, but they were very different. One was very serious, devoted to duty and had to be reluctantly pushed into the spotlight. The other was frivolous, fun-loving and enjoyed being the centre of attention.

More than 50 years on, the relationship between the future Queen and her younger sister is again being played out, this time in the form of Princes William and Harry.

William has been the model heir to the throne. No whiff of scandal or trouble has surrounded him. The whiff around his younger brother, on the other hand, has sometimes had a distinctly dodgy edge. Even when it wasn't due to cannabis.

His scuffle with a photographer outside a London nightclub yesterday is not the first time his name has been tarnished. It's not even the first time this month.

It was just a week ago that he was accused of cheating in his art A-level, when his former Eton teacher Sarah Forsyth claiming she helped him get the grade he needed to get into the Sandhurst Military Academy, where he is due to enlist early next year. A scratchy tape was produced to support her allegations, where he seemingly admits he "did about a sentence" of his coursework, but the exam board decided there was not enough to investigate the claims.

But it is not for nothing that Harry has acquired a reputation as the Playboy Prince. Prince Charles tried the shock treatment when he sent him to a drug rehabilitation centre after learning his youngest son had smoked cannabis.

Harry was a frequent visitor to the Rattlebone Inn near his father's Highgrove Estate, involving him in allegations of underage and after-hours drinking, as well as claims he verbally abused a French employee. Now, most of his partying seems to take place in London, where he is frequently pictured surrounded by beautiful girls and drunken pals.

And when he is not partying, he is playing polo, occupying a world far removed from that of most of his brother's future subjects.

NOT surprisingly, Clarence House has been furious at claims of debauched and louche behaviour, and suggestions that Harry spent his gap year partying, although many doubted that it was just fortuitous that his trip to the Australian Outback coincided with the rugby World Cup, particularly when he was frequently pictured having attached himself to the England team's entourage, beer in one hand, blonde in the other.

Now it seems that his reputation has been so sealed that even film broadcast earlier this month of Harry working in Losotho in southern Africa will not alter it.

Given his track record, it is hard not to see Harry as in the mould of Princess Margaret, whose life was blighted by scandal, marital infidelity and ill-health brought on by excess. And it cannot be a coincidence that both occupy the same position in the Royal Family.

"It is the Princess Margaret syndrome. He has got a different position to Prince William and that is why his behaviour is different," says Anita Atkinson, royalist and magistrate who has a listing in the Guinness Book of Records for having the largest collection of royal memorabilia.

"Elizabeth was the one who did everything right, who was dutiful and didn't put a foot wrong, and there was mischievous Margaret, doing everything wrong she possibly could.

"William is the one who is destined for everything, and Harry is the one destined for nothing."

It would be easy to attribute Harry's behaviour to losing his mother just two weeks short of his 13th birthday, but the truth may be more that he is behaving like any other 20-year-old would, without any of the responsibility that wears on his brother's shoulders.

"If he wants to go to nightclubs and come out at three in the morning, then he is just a lad being a lad, but when you come out and find a camera stuck in your face, then you would probably react to that," says Mrs Atkinson, from Fir Tree, near Crook in County Durham.

"He is in a goldfish bowl and I don't think you ever get used to it. When he goes to bed at night and wakes up in the morning, he is Harry of Wales, and he is never going to get away from that."

BUT any feeling that Harry is under unfair pressure is a reason to abolish the monarchy, where celebrities are born and have no choice in the matter, reckons Dr Martin Farr, lecturer in British history at Newcastle University.

"It is a very good republican argument, saying why should children be put in the public attention in this way?" he says.

"If they're going to go into public spaces like this, it is inevitable that they are going to get attention. The Royal Family has to be accountable to justify themselves, and that means people need access to them. You can't claim they're out of bounds.

"People will be divided into thinking it is ok for young people to suffer like this, and thinking it is rather a strange system."

Dr Farr, too, says the parallel with Princess Margaret is illuminating, although it must also be a worrying one for Harry's father.

"Great aunt Margaret is an example of someone who wasn't the heir and had all these pressures, but none of the feelings of responsibility or the feeling that ultimately her life would be resolved. So she went off the rails.

"Without the responsibility his brother has, Harry will be much more prone to doing this sort of thing. He is also a rather more impetuous fellow than his brother, and more likely to get into trouble, so I think we will see a lot more of this."

But although Harry will cause Prince Charles many more sleepless nights, his antics do not necessarily spell bad news for the monarchy as an institution. If every family has its black sheep, then it may be that Harry is carving out his role in the world's longest-running royal saga.

"I suspect most people will just regard it as a soap opera, and like a soap opera it will be popular and they will want to see it regularly," says Dr Farr. "The thing the Royal Family most want to avoid is indifference, and this will help make sure they don't produce indifference."