

It's the sheer unpredictability of the Mercury music prize that makes it so charming. Ahead of this evening's ceremony, former judge Trevor Dann remembers the difficulties of choosing a winner

Since the Mercury music prize nominations were announced in July, the usual criticisms have been doing the rounds: the organisers fiddle the result behind closed doors; big bands which might win Brits are not allowed to win the Mercury; the judges are instructed to nominate albums from the classical, jazz and folk genres but these are also expressly forbidden to win; it's all record company hype paid for and managed by the multinationals as a kind of Nationwide League for British music - an annual second prize for the artists who don't quite cut it in the pop premiership.

But like most British institutions the Mercury is more susceptible to the cock-up than the conspiracy. This is, after all, an event still named after a now-defunct telephone company even though it has a shiny new sponsor in Panasonic.

It was conceived in the early 1990s by Jon Webster, then MD of Virgin Records, who envisaged it as "the Booker Prize of the music industry". It would be independent of both the record companies and the music retailers, but endorsed by both. Its serious image would encourage ageing music fans to explore new albums as well as buying CD copies of their old vinyl favourites. And it would promote modern music as "art".

To ensure its independent status Webster chose Professor Simon Frith, a respected academic with a long history of writing about youth culture and media issues. And to keep Frith honest, the panel of judges would be selected not by him but by the event's organiser, David Wilkinson, from the ranks of UK music journalists, broadcasters and producers.

Wilkinson secured the Cable & Wireless subsidiary Mercury as a sponsor, launched the event in 1992 and has run it through his own company ever since. It is non-profit making, although Wilkinson and his partners seem to be able to live off it for 12 months of every year. Frith remains its chairman, receiving a small stipend and expenses. The judges are unpaid.

Being chosen as a judge feels like an honour but rapidly becomes a burden. This year's panel have been asked to plough through 183 entries. The organisers pretend that all the judges have heard all the albums but it's plainly impractical to consume upwards of seven days' worth of new music within the six-week judging period, so the first selection happens when each judge opens the box of entries and decides which CDs to bother with.

Judges submit a list of 10 albums they would like to see on the list of nominations. Frith then produces what he calls the "long shortlist" which numbers about 30 records. At the first judges' meeting he goes through the list and asks for volunteers to speak for each album.

Records with no supporters at this stage are eliminated. Then the judges speak for a minute or so about each nomination, and after a lengthy discussion, Frith lists the albums he thinks have the least support and asks if anyone minds them being knocked out. Inevitably someone does so the process goes on (and indeed on) for hours until the final list of 12 emerges.

As befits his academic credentials, Frith is a forensic, pernickety, often maddeningly proper chairman. He describes his role as "getting a sense of the meeting", encouraging the less vocal judges to speak up and humouring the big mouths who want to bully the panel into accepting their choices.

But blimey it's exhausting. Think 12 Angry Men meets Never Mind the Buzzcocks. By the time the list is agreed you wonder whether you like music at all.

And it's not over. Six weeks later the judges meet again on the afternoon of the awards ceremony itself in a private room at the Grosvenor House hotel. Frith follows the same painstaking process and gets the list down to three or four before the panel break for dinner. Then, as the bands are already playing and the cameras are rolling downstairs, they try to agree on the overall winner.

Regularly the discussion is so protracted that Frith has to literally run downstairs to give the final verdict in time to hit the news deadlines. Remember his dishevelled appearance when he announced Pulp's victory in 1996 and hastily invented a second prize for Norma Waterson, the cost of getting a last-minute consensus from the panel? Or the year after when he called Roni Size "Roh-nee" instead of "Ronny"? These are not the actions of a cool conspirator.

In fact, Frith confirms that the winner is often not a record he likes at all. When he was called on to give a casting vote between Gomez and Cornershop in 1998, he would have chosen Catatonia. I was on the panel myself that year and I find it hard to justify why we got down to those two from a list which included Robbie Williams's first solo album and the Verve' s classic Urban Hymns.

But it's the sheer unpredictability of the Mercury that makes it so charming. Don't ever believe anyone who says they know who is or isn't going to win.

And has it achieved its original objectives? Do the record companies see the benefit from their £170 entry fees and their £2,000 tables? Well some of the past nominees - Shara Nelson, Mark Morrison, 4-Hero - are remembered as often and as fondly as the original sponsors Mercury.

And it does seem odd that Oasis, Blur, U2 and Radiohead have never won a prize that's gone to Portishead, PJ Harvey and Primal Scream. But providing they get their marketing strategies right a record company can add about 150,000 sales on a winning album. And who can deny the positive effect of the Mercury on the careers of recent winners Badly Drawn Boy and Ms Dynamite?

What the Mercury Music Prize, gives us in Simon Frith's words is "a snapshot of the UK music scene" in September every year. It's not perfect, but anything which promotes and nurtures new British music needs to be sustained and supported.

· Trevor Dann is a former Mercury prize judge and the former head of BBC Music Entertainment, responsible for Live Aid, Top of the Pops and Whistle Test.

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