When you're a Spice Girl, an ex-Princess or a Gallagher brother, travelling on business becomes a military operation. Business travel for celebrities is, it seems, a minefield of screaming fans and ever-present paparazzi, with no chance whatsoever of browsing through the paperbacks at WH Smith. With nine licenced photographers allowed to walk "airside" - beyond customs - at Heathrow and Gatwick, you're not even out of danger in the VIP lounge.
Fortunately, there are a number of specialist travel agencies on hand 24 hours-a-day, 365 days-a-year, which will help smooth your journey, so that all you have to do is worry about which dark glasses to wear. Exactly who is on their books is however, a more closely guarded secret than the date of the Gallagher-Kensit nuptials.
"Our biggest selling point is discretion," says Andrew Douglas of Travel by Appoint-ment, a travel agency for people in the music and entertainment industry. "We might be privy to certain hotel arrangements for instance, and are under instructions not to divulge anything. It's vital that we maintain that trust."
Alan Newing, travel manager for Trinifold Travel, another agency for the stars, is equally tight-lipped, "We have a very enviable client list," he says pointedly. "In fact there is no major UK or US act that hasn't had dealings with us, but that's all I'm saying." The Travel Company, which specialises in organising travel for the film industry imposes similar self-restraint, although the company does admit to having organised travel for the James Bond film crew two years ago.
So apart from a wall of silence, what do celebrities get that the ordinary business traveller doesn't? Private jets, for a start. "The very high profile household names travel purely by private air charter with luxury facilities," says Douglas, although Johnny Hopkins, press officer for Oasis, maintains that the boys have been known to travel by train. "Sometimes it's the easiest way to travel and you get there quicker." British Rail's successors would be proud, but I'm not sure I believe him.
All the travel agencies have VIP Meet and Greet programmes, so the star can be whisked from car to airport and back again with as little or as much fuss as required by their PR agent. And it's not just the celebrity that needs to be kept happy. Getting a star to their plane without the terminal being brought to a stop by screaming teenagers is as important for the airport.
So, it's tough at the top, as the saying goes. But my bet is, it's harder for the travel agent. If you've painstakingly organised a band's World Tour, booked fifty crew members into hotels over several months, reserved entire hotel floors for one individual and organised everything from macrobiotic diets to oxygen tents in each destination, then re-organising the entire schedule when a leg of the tour is cancelled could presumably wipe the smile off the most star-struck travel agent's face.
"Fortunately we've got very innovative technology," says Douglas. "If dates are suddenly re-arranged, our system will automatically fax the hotels and notify them of the changes. In this business everything is very last minute, anything can happen and the smallest error can be disastrous."
Which brings us to the notorious celebrity ego - isn't satisfying the stars a precarious business? "As a person's celebrity status grows they are more able to redefine their preferences, because they are have become more exposed to a wider range of possibilities," says Newing, with the utmost diplomacy. "But you get used to never taking anything for granted. Someone can be a meat eater on one trip and a vegetarian the next, and you get it in the neck if you get it wrong."
So apart from being able to have tantrums over what you have for dinner, re-arranging your schedules at the last minute, enjoying the utmost luxury at all times, having your own private jet and being met at the airport at any time of the day or night, how does one know when you've "made it" in the celebrity business travel stakes?
One way is if you are invited to be an American Express Platinum Card holder, which for the price of a celebrity hair cut (pounds 375) will provide you with a personal account manager who can arrange for your shopping to be done without you having to leave the hotel and be mobbed and gives you special privileges and upgrades at more than 180 of the world's most exclusive establishments (although presumably, if you need upgrading, you haven't made it after all). For those who have fame but not fortune, it can also save you up to 40 per cent on flights, hotels and cruise lines. Fergie is, no doubt, delighted.