The caring traffic warden? Now there's a rare epithet for such an unloved member of urban society. Yet that was the label granted to Hakim Berkani after an employment tribunal this week, when he claimed he was sacked for refusing to bow to pressure to "extract as much cash as possible, via both fair means and foul, from the motoring public" while working in the London borough of Kensington and Chelsea.

As a fellow well-intentioned former warden, Darrell Lee Powell, can testify, there's a reason for the job's poor public image. Though most of his colleagues were decent and fair-minded, in his two years as a warden Mr Powell saw every duplicitous, cynical and downright fraudulent trick going.

One warden would stick a sign across the front of a working meter declaring it out of order before driving away on his scooter. Gone for just 15 minutes or so, he knew that one driver after another would spot the opportunity to park for free and fill up the bays. Little did they know that the devious warden would soon return, rip off the sticker on the meter, and start gleefully issuing a hatful of tickets.

Since Mr Powell was sacked four years ago – an interesting tale in itself – he has documented plenty such stories in a 517-page book, also available available online. Warden Stories 5102 is unlikely to become a bestseller, but its author hopes it will help fair-minded wardens to do their job better, as well as pushing authorities to tackle some big problems.

It's not all bad, though. Mr Powell feels he and many of his colleagues did a good job for the people living on their patches. "I see the job not just as giving out tickets," he says. "I helped keep an eye on the community. Some are too proud and overzealous. But the majority of wardens are very good people doing a difficult job."

He worked a wealthy patch in Westminster and claims to have been Kate Moss's favourite traffic warden. Realising that he could help rid her doorstep of the paparazzi who would always park illegally outside her house, the supermodel began calling Mr Powell on his mobile to request that he come and issue them tickets, forcing them to leave the house long enough for her to escape.

As Mr Berkani's tribunal has shown, however, even wardens with such good intentions can find themselves in trouble. A spokesman for the parking firm NSL said the company was "very strictly regulated to ensure any tickets issued are legitimate". But after his time working in the trade, Mr Powell believes that some private companies act like "cartels" with local authorities. Instead, he thinks the job should be done by police community support officers, who would not be pressured by bosses anxious to secure enough tickets to have their contracts renewed.

Contrary to what many drivers think, wardens are not motivated by commission, he says. "The bonus money wasn't that great, an extra £65 a month, and to get your bonus you had to jump through all kinds of hoops." The pressure came instead from management: "I got told more than once: you've got to do more tickets, more tickets, more tickets." He had to issue an average of 10 tickets a day on foot, and 15 a day on a bike – though he knew one experienced warden who could legitimately hand out 50 in a single day by targeting the right spots.

But some of the means used to secure fines were dishonest, Mr Powell alleges. While he was in the job, wardens were obliged to issue tickets and then photograph the cars before their owners drove off. If a vehicle was removed before a penalty notice could be issued, the ticket had be abandoned.

Mr Powell knew some wardens who would take the photographs first, altering the clock on their cameras by a few minutes to conceal their intentions. They could then claim to have issued a ticket even if a driver had got away. On receiving a letter telling them they were being fined, the driver would rightly claim to have never received the ticket, but the photograph would seem to prove otherwise and their protests would be ignored. Mr Powell even believes it was the prevalence of such "corruption" that led to a change in policy, allowing tickets to be approved without being issued on the spot.

It was not corruption that brought an end to Mr Powell's career. As a joke, he foolishly allowed a paparazzo to photograph him wearing a self-designed T-shirt bearing the slogan: "So you got a ticket? I don't give a FCUK!" It appeared in the newspapers, and his bosses were not impressed.