Adrenalin is high. Two hours later, her kid has left for school, her cleaner has gone in and her PA has arrived and given me a withering look. There are still no other 'paps' about and I'm starting to hope that I might just get that exclusive photo. I'm a big fame hunter, an urban sniper on the track of one the 'Big Five' that keep celebrity magazine covers happy. The other four are Gwyneth, Sienna, Keira and (at the moment) Kylie.

Another hour passes and the first rival pap turns up. Half an hour later and the street's totally packed with poachers and I realise that the game is up. Despite my attempts to blend in, one of them eventually recognises me and it's a sudden minor feeding frenzy ? like hungry goldfish around a tiny feed. Paparazzi are the only truly honest yardstick of where you stand in show business. If they can sell your picture, they'll snap you. If they can't, you'll be ignored.

The paps laugh at the idea that I arrived here at 8.30.

"She's not what you might call an early riser," says one rough looking character in a beanie hat, blue jeans and a Carhartt anorak. " She didn't get in until 3.30 this morning, she won't be up until the afternoon, at least," adds another scary-looking guy in paint-spattered tracksuit bottoms and a dishevelled duffel coat. In fact, as I look around me, they're all slightly scary, haggard-looking figures who all look a lot older than they really are.

'Snapping' is not an old man's game - it takes it out of you. But I've been doing it for two days and I'm embarrassed to say that I love it. Where some might loathe the waiting, I thrive on it. I love the banter, the competition, the adrenalin. I love the high when a tip-off comes good or you manage to get a shot that no one else has got. The fact that a really good shot could net you up to £1m is the absolute clincher.

I'm in Canary Wharf, east London, the afternoon of the Wild Hogs West End premiere. I've got a strong tip-off from my 'pap' mentor, Martin, that some of the film's stars - John Travolta, Ray Liotta and Tim Allen - are staying at the Four Seasons. Security is tight, with man-gorillas wandering around the car park. Martin and I agree on a cunning plan, making use of my minor celebrity. The irony is that Martin is too well known, but I might just get away with it.

We've got a tinted Chrysler people carrier ferrying us around. It's very much one of the celeb vehicles of choice. Martin sets up my camera for me so that it's primed to shoot properly through the dark glass. I lay it carefully on the seat, ready for action. Then I'm driven to the door of the hotel. I get out, nod to the security monkeys and enter the hotel as though on some important TV comedy business. I sit down in the lobby bar nursing a beer and reading a newspaper, while keeping an eye on the front door.

Our Chrysler has left the car park and is parked round the corner waiting for my call. Suddenly I see an American, movie-looking guy at the bar and he's on the phone. I sidle up and eavesdrop. He's telling someone that 'The Hogs' are leaving the hotel at 10 past. Bingo.

Surrounded

At seven past, I see Ray Liotta arrive in the foyer surrounded by his security goons. The Chrysler glides up to the front door to collect me. The security people ignore my transport and me, as they're now wholly focused on their clients, all assembled on the other side of the revolving door. I jump into the van and we pull away, turning round fast to face the front door. I've got the camera in my sweaty hands. I'm the sniper in his nest, stroking the trigger, I'm ready for the kill.

Liotta comes out first - his car's not quite ready, so he wanders towards us, chatting into his mobile phone. He stops about 5ft from my window, yakking away. I can't believe it. I fire off about 15 frames, trying to keep my adrenalin under control. Travolta and Allen suddenly exit the building.

I level my rifle (sorry, camera) and snap away, the security guys are blissfully unaware of our presence. Everyone in our van is holding their breath. As the 'Hogs' all get into their matching Mercs, we speed off out of the car park in a great exhalation of excited breath.

The security guys become aware of our alien presence for the first time, but it's too late. The camera crew, the driver and I all start screaming with excitement and release tension. It's such a buzz. This is the drug that keeps paparazzi going. For a real pap this would just be the beginning. He (it's pretty much exclusively a man's game) would have to get on to his laptop ASAP. He'd upload the photos and send them to his agency or picture desk and pray that he had the exclusive. Only then is their money secured. As it turns out, most of my photos are out of focus. I am too excited and inexperienced, but there are a couple of useable frames. I feel like the king of the world. And yet, when I actually sit down and analyse what I've just done - got some exclusive photos of three film stars who are in town with the sole purpose of promoting their film and gaining maximum exposure, I get a tad confused. I wonder who's actually fooling who? It's like when I get a 'tip-off' about Natasha Bedingfield. It's frighteningly accurate. The singer will be arriving at Selfridges' Duke Street entrance at 9.55am on Wednesday morning, to do some shopping. I'm there on Wednesday morning and so is Natasha, bang on five to 10.

Friendly

She's very sweet and friendly to me and doesn't seem at all surprised that I'm there. She has a new album coming out and nice unthreatening shots of her holding a Starbucks latte and going on a shopping spree are great publicity and grist to the celeb magazine mill.

Back in Kate Moss's road, it's now past midday with still no sign of the nation's highest paid clothes horse.

I start chatting to an Albanian pap. I ask him which celebrity he dislikes the most. He doesn't hesitate - Jude Law. Around me every pap agrees. They all hate Jude Law and they've all got stories about him.

"His real name is Dave," says a very young pap with slightly crossed eyes.

"Do you know he's actually from Lewisham? When he turns up to premieres we all shout, 'Oi Dave, over here' and he ignores us, it's really funny."

One quietish guy in a van with a little dog at his side tells me a blinder: " I spotted Jude Law walking around Primrose Hill and I started taking pictures of him. Suddenly this elderly resident runs up to me. She starts telling me to leave him alone.

I tell her to calm down, he's a celebrity after all and he's in a public place and I'm only taking his picture, it's not the Third World War. Suddenly, Jude Law runs up to me, he's been listening in and his face is twisted with rage. He shouts, 'I'm an actor, not a celebrity'. From then on he's known by all us 'paps' as Celebrity Dave."

Just as I'm trying to write everything down, the man in the van with the dog whispers to me that he's about to go and snap Madonna leaving a gym. Do I want to join him? The adrenalin snaps in again and we're off.

Ten minutes later we're in a back street in St John's Wood outside a nondescript estate agents. Underneath is a tiny gym, and this is where Madge is currently exercising her royal muscles. Her car, a blacked-out Audi, is waiting outside and there is about a 20-yard killing zone where I'm going to have to get my picture. We are all set up when a slightly camp traffic warden on a moped suddenly zooms down the road. Most of the assembled paps jump back into their (universally shabby) cars and drive away to avoid a ticket.

The big Albanian 'pap' tells me that there is a rumour that this traffic warden is actually a 'pap' himself. He shoos everyone away and then gets the scoop himself. No one trusts anyone in this game.

Sweaty

Two minutes later, all the 'paps' are back in place waiting for sweaty Madge. Madonna comes up the stairs and I fire off 10 shots and feel confident that I've got her. The man next to me has a camera that takes up to 10 frames a second. He knows he's got her. I decide to ask her a question, give myself a bit of a story. For a second, I toy with asking her whether she's realised yet that her husband is a Mockney idiot. I decide against it and shout: "Madonna, it's my first day as a paparazzo, how am I doing?" She laughs, but doesn't answer me. The Audi speeds off. I'm congratulated by the assembled lens jockeys. I made Madonna laugh, and rumour has it that she hasn't laughed in public since she married Guy.

I meet the Albanian again two days later. Kate Moss finally awoke at 5.30 in the afternoon. They didn't get a picture.