Betfair - where winners have just become losers

The life story of the Betfair betting exchange is relatively brief, but it has certainly packed a lot into its nine-year existence. From a tiny start-up, fired by the vision and genius of its two founders, Andrew Black and Edward Wray, it has grown into a billion-pound business, with hundreds of staff in plush riverside offices, customers in dozens of countries, and a Queen's Award for Enterprise nailed to the wall.

And amid all the staggering numbers, there is another, less tangible, achievement. Betfair is now one of the world's biggest betting businesses, yet it has always managed to retain a public image of the pioneering start-up, defying the corporate norms. Many of its clients still feel like members of a club, and have the same sort of regard for Betfair that Apple-fanatics do for their Macs. This has always helped to keep them "sticky", and allowed Betfair to defend its near-monopoly.

The loyalty of some customers may be tested to the limit, however, by Betfair's decision, announced yesterday, to introduce "premium charges" for some of their biggest winners. Betfair insists that the new charges will affect "less than 0.5%" of its customers, but still seems to stand in complete contradiction to the company's oft-repeated boast that this is a place "where winners are welcome".

The charges, and the conditions under which these will be incurred, are explained in a 1,200-word posting on the Betfair website. The rules are, clearly, quite complicated, but plenty of their customers are starting to consider the implications. One Betfair client who contacted the Guardian yesterday said that if the charges had been imposed over the last few weeks, he would have been forced to pay "a five-figure sum".

"They think they can do it because they have an effective monopoly. I look forward to their next advertising campaign. Instead of 'where winners are welcome', they can say, 'come to Betfair, where winners get screwed'," he added.

At least one of Betfair's winners, though, took a different view. "It's the best news I've had for ages, as it's not going to cost me a penny," Harry Findlay, professional punter and owner of Denman, said. "I'm a gambler, so the way I bet, it won't make a difference. The people who will be screaming will be the maths professors with computer models, the ones who just never lose. If they clear off, it should be even easier for me to make money."

Even so, Findlay could still appreciate a basic problem with Betfair's move. "I'm in favour for selfish reasons," he said, "but when I first heard about it, I thought it must be a joke, as it's so completely against the ethos of the whole company." Betfair's enemies in the racing establishment may also be interested in the news. After all, if Betfair itself can cream off an extra charge from people who must, in effect, be running a business on the exchange, why can't the Levy Board do it too?

Betfair was started by punters, for punters, and has transformed the betting landscape in less than a decade. Yesterday's news, though, could mark the moment when it stopped being a plucky start-up, and turned into just another faceless corporation.