It's 8am in the lobby of the Hammersmith Novotel, and three transvestite grannies are sharing sofa space with a squawking parrot and a burly, middle-aged man bursting out of a Union Jack waistcoat and suit. A late arrival enquires: "Is this the Britain's Got Talent auditions?" – a question which, in the circumstances, appears entirely superfluous.
When the doors to the misleadingly titled Champagne Suite are flung open, this year's collection of the deranged, deluded and – just maybe – genuinely talented rush toward the waiting cameras, primed for imminent SuBo-style fame.
As a media journalist, this would normally be as close as I get to the inside machinations of Britain's most popular entertainment show. But here I am, being ushered through the doors, alongside the conjurors and ill-advised male strippers, in my capacity as adviser/friend/svengali figure to one of today's quarter-finalists.
Simon Cowell doesn't know it yet but Brassroots, an eight-piece multinational horn-and-percussion ensemble, who pump out funky versions of rock and soul hits, are the global sensations he is searching for.
In fact, the experience of trying to outmanoeuvre television's most prominent impresario and his all-powerful Syco production team would eventually leave a discomfiting sensation – I ended up actually feeling sorry for Simon Cowell. First, though, we have our dream to chase.
Bleary-eyed and unshaven, Brassroots huddle around their instruments in the pre-audition, interview suite. An army of young, female producers in headsets and matching Britain's Got Talent blue sweatshirts assess the televisual potential of the latest hopefuls. Smiley and helpful, the Syco-ladies also possess a distinct "don't mess with us" glint.
"You don't look like your pictures," says a Syc-ette quizzically, glancing at the band. Brassroots have made a "continuity error" by not wearing the same clothes that they modelled at their successful Islington audition. This makes it harder for Syco to stitch together footage from different auditions.
The cameras move on to a more promising target, the Union Jack-clad gent, Patrick, a pub singer from Essex, who wants to put the "great back into Britain". Has Patrick been on TV before? "Only on Crimewatch," his son jokes (I think).
"We need a narrative, a story for the cameras," I advise Jerome Harper, 34, Brassroots's founder member and trombonist. Born in Brooklyn, he studied music in Texas and has played every gig from Norwegian cruise lines to Glastonbury.
But is that enough to prick viewers' sympathies? Susan Boyle dreamed a dream, from Scottish spinster to stardom. What have we got? Well, Jerome lived in New Orleans for a few months and left some possessions there before the hurricane. "So, you lost everything in Katrina?" Well, it's a start.
The suite has filled up with more contenders. The cameras love Myztikal, a teenage street dance group in matching uniforms from south-east London, who have brought numerous "friends and family".
The squawking parrot perches on the shoulder of a woman who bears an uncanny resemblance to Mirjana, the widow of Slobodan Milosevic. But there doesn't seem an awful lot more to the act than that.
Brassroots are ready for their interview. Jill, who will pose the questions, soon learns that this bunch of serious jazz-heads may not provide the most scintillating of soundbites.
In fact, Brassroots aren't really sure if they want to win the series. "Susan Boyle earned £8m last year. How about that?" offers Jill. "I've got session bookings, would I have to cancel them?" asks practical trumpeter Charlie.
Sadly, Jill doesn't prompt Jerome to relive his tearful Katrina tragedy. But he says that winning the show would show young kids that brass bands can be cool. It's a good line – so good, in fact, that Jill gets Jerome to repeat it several times, in different permutations, until it's a perfect "grab".
"I had the unbelievable urge to tell them that I was the son of a share- cropper following my dream to Europe to make it as a big pop star trombone player," confides Jerome. "I felt wrong for being just a musician. And I kept forgetting to include the question in my answers."
Ant and Dec, the people's champions, slip unnoticed into the suite. "Ant and Dec are in the room," a producer announces. "Do not take any pictures of Ant and Dec. Do not approach Ant and Dec unless they talk to you." The duo mug for the cameras with Mrs Milosevic and her feathered friend but give Brassroots a wide berth.
Brassroots, who haven't eaten or drunk anything for five hours, spot a crate of bottled water. Not so fast. "Water is for the crew only," instructs the Syc-ette. "You can buy food and drink from the hotel bar." A couple of Brassroots drift off for a jazz-friendly "smoke" instead.
There are just minutes to go until the contestants are ferried by coach to the Hammersmith Apollo, where 3,000 fans have been queuing all morning to see Cowell and his panel tear into this year's acts. It's at this point that Brassroots are asked to sign a release form which would make the band a wholly owned entity of Syco and any associated entities "hereafter invented throughout the universe".
Syco is entitled to "exclusive worldwide recording, management, touring and merchandise" agreements. The producers are also free to "alter, adapt or make additions" to the performers' appearances at their discretion. A special clause for illusionists absolves Syco of any responsibility for revealing a secret trick should viewers slow down the footage.
The band want the Musicians' Union to look over the agreement. "Sure, but we need it signed and returned in 10 minutes." It's too late to turn back now, so the agreements are signed so that the band can finally do what they came here to do – play.
Inside the Apollo, a warm-up man has worked the crowd into a frenzy. Piers Morgan, Amanda Holden and the "villain" Cowell are received like conquering heroes. Amateurish acts, which test the patience of the mob, are jeered until the judges put them out of their misery.
Security staff prevent the audience from filming acts on their phones. YouTube audition clips, watched and shared by millions, are now too valuable to ITV for fuzzy homemade versions to appear prematurely.
The judges, we are told, have never seen the acts before. Myztikal screw up when their lead vocalist goes seriously off-key. "It was like a community centre theatre group," sniffs Cowell. Earlier, they looked like contenders, so the elimination of a rival must be good news for Brassroots. But Cowell, "going with my heart not my head", waves Myztikal through.
Union Jack Patrick belts out a singalong "Daydream Believer" and dedicates his performance to the "British bulldog". But he also promises to dedicate the £100,000 prize to The Sun's Help For Heroes campaign, so the judges can hardly refuse him passage.
Syco pound-signs really start spinning when Kayim-Ali, a four year-old Michael Jackson impersonator, shuffles nervously on stage. The audience and panel issue a collective "Ahh ..." as the little boy works through his repertoire of "Smooth Criminal" moves. It's perfect YouTube fodder and a star is born. There's just a nagging doubt that Jackson's own early-years entry into the brutal world of showbusiness hardly made for a happy life.
And finally ... here's Brassroots! A brisk fanfare of the 20th Century Fox theme and we're straight into "Seven Nation Army". The group come alive, punching the air with their instruments. The audience responds, and soon 3,000 people are on their feet, clapping to the groove. Cowell tries to get the crowd to make less noise so the judges can actually hear the band. Brassroots segue into Inner City's "Good Life" and finish to rapturous applause. They must be a shoo-in, even for the toughest panel in showbusiness. "Great fun," enthuses Piers, awarding a big tick.
Cowell takes a deep breath. "It was ... OK." Pardon? "There weren't enough of you," he tells a nonplussed Jerome. "There should be more of you." No problem, we'll airlift over every unemployed brass blower from New Orleans, just let us through. But it's a "No" from Simon.
It's all down to Amanda, lovely, kind-hearted Amanda. "We see a lot of brass brands here," she says. "But you guys made brass bands modern, funky and cool. I'm putting you through!"
Yet even as Brassroots give their instant elated reaction to Ant and Dec, there is a sting in the tail. "You'll be coming back on Friday for the Reveal Day," says a producer. "Please wear the same clothes as the audition. No need to bring your instruments."
"Reveal Day"? The panel has spoken, turfing out timewasters and sending the talented chosen few through to the finals. Surely it's now down to the television audience to choose a winner on artistic merit?
But no, the blue sweatshirts and headsets are organising a separate talent cull at the Grand Connaught Rooms. In the Syco star chamber only those who give great TV, who can emote for the camera on cue, can fill tabloid newspaper spreads and are willing to throw their dignity to the four winds, will survive.
The Connaught Rooms are where dreams of stardom go to die. This is how Jerome described the band's experience there: "We sat around for over 10 hours for them to escort us on to a stage for about two minutes to say, 'Sorry, you didn't get through'. After the on-stage 'reveal' we were rushed in front of a camera to express our deep sadness and disappointment that the TV gods had decided we were talentless. I have a feeling they didn't like my response."
Cowell might have dreamt up Britain's Got Talent, but his army of blue sweatshirted drones has risen up. One day, perhaps, they will decide that Cowell has served his purpose and terminate him.
Brassroots, meanwhile, are happy to return to their Bethnal Green club night. Perhaps a fleeting clip of them will survive when Britain's Got Talent screens those hilarious moments from the auditions.
"I think the producers were definitely looking for something other than talent, and the way we were eliminated was annoying," concluded Jerome. "But performing at the Apollo was absolutely incredible and the audience loved us."
If it's any consolation, I tell the band, the parrot got culled, too.
Brassroots play Rich Mix, Bethnal Green Road, London on 9 June and the Glastonbury Festival 25-26 June