The addicted in search of the evicted

It's not just the contestants who have had their lives changed by Big Brother

Once you're in, there's no going back. Flanked on the right by razor-wire metal fencing and on the left by a wide canal, it's a brisk forward route only. At checkpoint number one tickets are efficiently scrutinised under a powerful beam of torchlight. An electric gate swings silently open and blinding floodlights sweep the ground from overhead. The gravel path winds round to the right. Some people break out into a run, but most choose to huddle up and walk in together. Another checkpoint and a thick set man in a dark suit barks orders into the night air. Once past this final barrier you're in, standing face to face with the waiting Rottweilers, each one straining viciously on the leash.

Once you're in, there's no going back. Flanked on the right by razor-wire metal fencing and on the left by a wide canal, it's a brisk forward route only. At checkpoint number one tickets are efficiently scrutinised under a powerful beam of torchlight. An electric gate swings silently open and blinding floodlights sweep the ground from overhead. The gravel path winds round to the right. Some people break out into a run, but most choose to huddle up and walk in together. Another checkpoint and a thick set man in a dark suit barks orders into the night air. Once past this final barrier you're in, standing face to face with the waiting Rottweilers, each one straining viciously on the leash.

There are no pop stars here. No royalty, no Hollywood superstars and not even Gail Porter. The few hundred people who braved the Colditz-style security are here to catch a fleeting glimpse of a mild-mannered young farmer from Ireland make a 50-yard dash to freedom. This is the Big Brother house on Friday night, where the show's devoted fans gather to get a momentary taste of live action. It's a night which no longer means post-work drinking, or winding down for the weekend. This is eviction night and this chilly patch of east London wasteland is the only place to be. "It's taken us two and a half hours to get here from Northamptonshire," says Martine Sheppard, who is pressed up against the barriers in the front row. "We got lost on the M25, overcharged for a taxi and couldn't find the Travel Lodge. But it's absolutely fantastic."

The build-up starts early. People start filtering out of Bromley-by-Bow Tube station from about 7pm and even then, four hours before the moment of eviction, they are prickling with anticipation. Tickets are like gold dust. Initially they were freely available over the internet, but demand has been so high that they have completely run out. A letter from the production company accompanies the ticket. "You will be involved in part of television history in the making," it says. "Please ensure that you and your guests are extremely lively and up for a fun night out."

The fun starts with a queue, a long and windy one which doesn't move for more than an hour. But for the people who've come from Chesterfield, Leicester, Peterborough and wherever else, time spent waiting is time spent debating. The sense of camaraderie is instant, as the point of connection is already established. No introductions are necessary. "Is Anna playing dumber than she really is? Is Darren really just an old queen? When is Craig going to get his shell suit out? Is it still worth watching since Nasty Nick got kicked out?" And so it goes on and on and on. As it has done everywhere else across the country for the last 47 days.

At 8.30 Brian, a business consultant from west London, whips out his hand-held television and tunes into the early evening show; the waiting crowds cluster round. Brian's something of an old pro. He's already witnessed Caroline get evicted and has tickets lined up for the final. "Friday night - what are your choices?" he asks. "Rush home to watch it on TV? Or come down here, see it on the big screen and get lost in the madness of it all?

"In 10 years' time, people will be talking about this. There are certain things that take place every decade and this is one of them, this is a phenomenon and coming here is about seeing a moment of our time in action. When it finishes, this nation is in trouble. Six million people will have to learn how to have conversations again."

When the Nasty Nick showdown started to unfold two weeks ago, Brian was at work. There was nothing else for it. He stuck his phone on voicemail, put his headphones on, settled down and logged on for a gripping three-hour session on the internet.

"In the first week it was just die-hards and mad people," says a member of the production crew. "It was really hard to get them going." But now, without so much as a prompt card or a warm-up man - and even with only half the crowd going via the free bar - the hysteria hangs heavy in the air. When Caroline got evicted earlier this month, euphoria erupted and trouble broke out. It was nothing serious; a few scuffles and a bit of shoving, but since then the aftershow bar no longer stays open until two, as promised on the tickets, and extra security has been drafted in to calm things down.

"Caroline came out to sign autographs," recalls Brian. "Suddenly loads of people started running towards her, screaming. She just froze and security had to pull her back in. The thing about this kind of celebrity is it's instant. If you're an actor or a pop star, fame is a slow process but only six weeks ago these were just ordinary people."

The house itself is clearly visible on the other side of the canal but here, wedged behind two rows of facing barriers, is as close as the fans get. There's another hour of waiting and the events in the house unfold on a big screen overhead. Every time Mel appears, the crowds boo and scream "whore". The fans are a broad mix. There's the City highflyer who's brought his entire office. There's the man who introduces himself as Sally Bass, president of the Anna fanclub, who's selling "Anna Big Sister" T-shirts for £10 each. There's the trendy gay contingent, the media blaggers, the TV groupies and the girls who simply fancy Craig. But mostly it's ordinary people, people who tuned into a TV programme and found, for the moment at least, that it changed their lives.

Martine Sheppard, 29, drove down from the Midlands with her friend and colleague Sara Jeffers and their husbands. Both are teachers at Brooke Western College in Corby. "I've changed my routine to fit in with Big Brother," she says. "Every night when I get in from work, the first thing I do is check the news update, then I watch the programme on TV, and before I go to bed I'll go online again for about an hour. We usually vote repeatedly. When Caroline was nominated I spent my life on the phone. When I heard we had tickets to come here I was over the moon, dancing round the front room giggling like a teenager. We've been talking about it non-stop for two weeks and when our pupils found out we were actually coming here, we were suddenly the trendiest teachers in school."

When Anna was nominated for eviction Martine sat down and wept. "She's my favourite, so I decided to ring and vote for Craig, but then I ended up having a bit of a fight with my husband. Like Craig, he's from Liverpool, so it caused a bit of friction. When it's over I'm going to cry. It'll be like losing a group of friends. I'm going to miss them. There's going to be a very big gap in my life."

The crowds, meanwhile, are gearing up to countdown. A member of the crew comes out and handpicks a group of girls. These are to be the Thomas fans. "Remember," he says, "you are the first people Tom will have seen in weeks. You've got to make a really big impact, lots and lots of noise. We'll give out cards and Biros and you've all got to try and get his autograph and take lots of photos." The group is ushered over to a pen at the nearest point to the house. An unseemly catfight breaks out, skirts rise up and high heels are kicked off as the girls clamber over the barriers for a front-row view.

The rest of the crowd in the meantime have become somewhat preoccupied by Marjorie, the Big Brother chicken. Earlier that day Craig had gone into the house's diary room to ask if the contestants could kill it and eat it. A lone animal rights protester dressed in a chicken costume had been flapping around earlier; another appeared later handing out "Save Marjorie" flyers. The crowd starts to chant and "Free Marjorie" banners strapped to old coat hangers are wiggled vigorously.

When Tom eventually emerges from the house he is whisked through the crowds in a flash. The "autograph hunters" perform their task admirably and, as the doors to the studio shut behind Tom, the mobile phones come out. "Did you see us," they shriek. "Did we get on TV?"