It's the non-stop party Prince

Prince Harry partied until the early hours today for the second time in five days.

He spent four hours with a group of female friends at fashionable nightclub Boujis, in South Kensington. The prince, who was seen drinking and smoking, left at around 2.30am accompanied by his Scotland Yard protection officers.

An onlooker said: "He came out laughing. One of the bouncers said he appeared to be quite merry. He spent much of the time in the VIP section." His night out comes just days after the 19-year-old was reportedly seen kissing and cuddling 20-year-old topless model Lauren Pope at Mayfair club China White, a popular haunt of soap stars, footballers and models.

Harry, who was dressed in jeans, a short-sleeved shirt, bodywarmer and baseball cap, was driven off in a Vauxhall Omega estate car.

His latest night out - only days before he leaves on an eight-week humanitarian visit to Africa - happened while his father Prince Charles was away on a diplomatic mission to the Gulf.

Club insiders say Harry, who favours vodka and cranberry juice shots, showed "no inhibitions".

Onlookers said the young royal mingled with the " incrowd" in the smoke-filled booths, some fashioned like beds, where guests sit on padded cushions, the cocktails flow and the atmosphere is seductive.

And although the prince is at that age when most young men venture into the night in search of fun, his remorseless pursuit of pleasure is causing some concern among Palace aides. Just a few days earlier he had been out again, this time in one of his favourite haunts, the So Bar on Fulham Road, where in recent weeks he has become something of a regular, drinking beer and texting friends on his ever-present mobile phone.

The bar, owned by Harry's mentor and former Army officer Mark Dyer, is not far from Crazy Larry's, another nightclub patronised by young royals. The prince's circle have dubbed it Crazy Harry's.

Harry is currently meant to be on an educational gap year. After the publicity he received two years ago for his drinking and drugtaking, he was said to have grown up and put these wilder excesses behind him.

Aides insist he has been keeping a lower profile than normal, remaining out of sight at Highgrove or at Sandringham, the Queen's Norfolk estate where he and his brother have hosted shooting parties.

They say Harry has been devoting time to widening his horizons beyond mere hedonistic pleasures, including learning about his father's extensive charity and business interests and doing work experience.

He draws companions from all walks of life - his only requirement being that they share his love for nightlife and partying.

Those close to Prince Charles say he worries constantly about his younger son and knows how easily he can be led astray.

And senior staff have expressed concern at plans for Harry to enjoy not one gap year, but two.

The official reason for delaying his entry to Sandhurst until September 2005 is that most cadets are aged at least 21. If Harry was to join this year, aged 20, he might have felt out of place.

However, close aides defend Harry. One said: "Although he can be a handful, he is just a teenager who likes to go out and enjoy himself."

Harry is set to travel to Africa - where he is expected to visit Kenya, Botswana, Tanzania and South Africa - within days.

He will work with organisations helping Aids sufferers, the homeless and other vulnerable people. It just could be the making of him.