In 1963, the Bishop of Kerry told the actress Diana Dors to leave the town of Tralee. The bishop was disgusted by whispers of a cabaret performance that left nothing to the imagination. Chased by reporters and a clutch of ageing bachelors, the actress decamped to Dublin, where she took a suite in the city's best hotel. Every night at six o'clock, two bodyguards collected a tray from the hotel kitchen. On it stood a pot of tea and a freshly baked apple tart, both for the resident celebrity. Each night, the kitchen porters made vulgar remarks about sex, tarts and Diana Dors. On the fourth and final night of her stay, a chef took the freshly baked tart, removed the lid and started to masturbate. After spreading a thin layer of semen over the puréed apple, he smiled at his colleagues, replaced the lid of the tart and garnished it with a sprig of mint. The plate was later returned to the kitchen, without so much as a crumb of complaint.

Anthony Bourdain's Kitchen Confidential is full of similar stories. The bestselling memoir about his early days as a chef in New York is a homage to the 'whacked-out moral degenerates, dope fiends, refugees ... drunks, sneaks, thieves, sluts and psychopaths' who work the pass each night. Are critics any less criminal? Look at the title of my book, Kitchen Con. Call it an act of worship if you wish. It was, in fact, a steal. Such acts are typical in the restaurant world, which is full of rip-off artists. Imitation explains why so many second-rate chefs survive. But a cook who dares to tell the truth? Now that's unusual. No wonder he did so well.

Given the behaviour of those who were privy to the apple-tart incident, it may surprise you to learn that men who cook for a living are quite a delicate bunch. Indeed, with the possible exception of gay hoteliers, there is no more sensitive a group of people than chefs. Scientists have recently discovered that chefs take more offence than Mary Whitehouse. That's why I am always shocked when they threaten to sue, or, worse still, punch my lights out. Both of these activities require a certain steeliness.

Some chefs even go to court over good reviews. In August 2004, one Phil Romano filed a 16-page lawsuit over a review of his new restaurant in The Dallas Morning News. Romano was furious with critic Dotty Griffith, after she dared to give the restaurant Il Mulino New York - another homage, no doubt - 3½ stars out of a possible 5. Griffith had claimed that Il Mulino's vodka sauce was 'finished with butter', and that the 'delicious' porcini ravioli 'whispered of gorgonzola'.

'I don't have any gorgonzola in the whole kitchen,' fumed Romano, 'and there's no butter in that vodka sauce.'

The newspaper issued a statement. Note the hasty, withering timbre. Sounds like a middle-aged lawyer who was stuck in the office on a Friday night, wife on the phone, dinner getting cold: 'It's clear from the complaint that the plaintiff recognises that the review was an expression of opinion, protected by the First Amendment. If this sort of claim were allowed to proceed, newspapers, magazines and others would have to defend unfavourable reviews of restaurants, books, movies and the like constantly. Since claims like this are not allowed under the law, the plaintiff has tried to concoct claims other than defamation - but those efforts cannot hide the fact that they simply disagree with the review. The disagreement, fortunately, is not grounds for a lawsuit.'

Romano was undaunted. 'They hide behind opinion and free speech, which is fine,' he told a reporter. 'I'm trying to critique the critiquer.'

The case was dropped, or settled, quickly. Life went on. Romano is still in business. He says it remains robust. Good for him? Not really. For the last 10 years, I have been issued with lurid threats on a weekly basis. Some of them are quite serious. No one likes to spend much time in court, as lawyers are so crooked that they even make chefs look honest. Fortunately, I can laugh off most complaints. The rest are sub judice.

There are several examples of culinary revenge that do not involve solicitors, which thus deserve to be celebrated. I am thinking of staff at a restaurant, Villager, where: the rosti was so thick and chewy it bore a strong resemblance to gardening twine; my partner could hardly touch the frazzled remains of some poor beast ... and the best part of the evening was when we were told that we couldn't order pudding, because the kitchen was closed - at 9.30pm.

The man who penned these remarks, Richard Bath, is a sports editor and occasional restaurant critic at a Scottish newspaper. He clearly thought Villager was fair game: 'Not since I left the Lighthouse in Leith with my stomach churning, my ears bleeding and my wallet empty have I vowed never to return to a restaurant. But vow I did.'

The restaurant's response was equally unambiguous. A sign appeared on the wall of the dining room: 'Richard Bath wears ladies' underwear.'

The most famous Irish chef is a young man called Conrad Gallagher. When a colleague of mine, Helen Lucy Burke, had the pleasure of dining at his flagship restaurant, Peacock Alley, Gallagher decided to spare her the nuisance of writing it up by issuing a solicitor's letter in which it was alleged that, on the night in question, 'Helen Lucy Burke ... appeared to be intoxicated, made little sense to talk to, in addition to slurring her words, and also made unnecessary disparaging remarks to Mr Gallagher's staff, eg, "Can you wrap this up, I want to feed it to my blind pussy?"'

Wine often clouds a critic's judgment. There are questions to be asked of all hacks in this regard. Answers, if any, are slurred. However, Helen Lucy Burke is a woman of rare integrity. Her moral probity is even celebrated in a song by Christy Moore, who refers to her 'mattress-sniffing' days as a hotel critic. Gallagher's decision to issue a solicitor's letter was designed to deflect attention from the contents of the review itself. Rather than issuing a strenuous denial, Burke's editor, John Ryan, decided to publish the solicitor's letter alongside the review - which, by the way, was quite sympathetic - allowing readers to decide who stumbled on the job: who had a leg to stand on, and who was utterly legless. The article was headlined 'The Peacock, the Critic and the Blind Pussy'. It marked, I think, the beginning of the end for Gallagher's empire.

In 2004, one Sarah Roe was accosted by the chef Tom Aikens as she tried to leave his London restaurant. 'Where,' asked Aikens, 'is my teaspoon?' The businesswoman had just settled a bill of £536, but Aikens wouldn't let her go until the spoon was found, on another table. What does this anecdote tell us about chefs? Does it illustrate their attention to detail? Does it suggest that too much time in the kitchen can also cloud a man's judgment? Perhaps it means that Aikens was wrong this time, but right, in general, to prance around like a young Inspector Clouseau.

I am suspicious of chefs who try to adopt the moral high ground, because the restaurant business is, and always has been, a front for the Kitchen Con. There is no spite in that remark: critics are just as greedy. Great chefs are entitled to have delusions, and figures like Gallagher and Aikens deserve support. At least they know how to cook. It's crooks with a rusty knife - and all their unscrupulous bosses - who epitomise the Kitchen Con. It is they who deserve to be exposed. Here, then, are 20 ways in which restaurants abuse their customers. I sincerely hope that you aren't familiar with every single one.

1. That special feeling

In a perfect world, specials would be, well, special. Made from seasonal produce that doesn't last long enough to become part of an à la carte menu, they would principally appeal to regular customers who want a little variety - and particularly good value. In the real world, specials are an excuse for restaurants to extract maximum profit from stale food. That Special Feeling is being ripped off.

2. Two-sittings tyranny

They used to call it the hospitality business. Hospitality means 'kindness in welcoming strangers or guests'. Have you ever told anyone that, unless they turn up for dinner in your house at half past seven and leave by five to nine, they're going to be turned away? That is what a hostess is employed to do. The tyranny of two sittings is a recent invention. It's one of the few good reasons for welcoming the prospect of a nice long recession.

3. Celebrity endorsements

A variation on the Hot New Place. Take one frightful new restaurant, find a couple of B-list celebrities, persuade a journalist to review it and bingo! Suddenly it's the Hottest New Place In Town. For evidence, read the social diary in any mid-market tabloid for longer than two weeks.

4. The white hole

How many times have you ended up paying nearly 30 per cent of your bill as a tip? Many restaurants slap on a 'discretionary' 12.5 per cent service charge, without even bothering to ask you if everything was all right. Then they hand you a credit-card slip with a hole in the space marked 'service'. Being a civilised but slightly tipsy human being, you assume that service has not been added. And you put it on again.

5. The hot new place

Journalists are paid to promote restaurants that would otherwise flop. The payment takes the form of a benefit in kind ('Why don't you and your pals come for dinner on Friday?'). It doesn't make anyone look good - except, of course, that exciting new place for dinner on Fridays.

6. When bread means dough

The cost of bread is traditionally factored into menu prices, just like electricity, say, or the rent on the owner's mistress's apartment. Lately, however, restaurateurs have grown tired of 'giving things away for free'. Naturally, the price of your bread does not become apparent until you have received the bill. Next up: restaurants to serve raw meat. 'You want that steak cooked? That's another fiver.'

7. Middling-bistro syndrome

Friday night. Your wife is tired and hungry. Good restaurants are booked out. You ring that middling bistro. It's not too pricey; they have a table. The reason it's not fully booked is because it doesn't deserve to be. When you examine the bill, you realise, shrugging, that for another tenner and a little foresight, you could have dined in style. Do yourself a favour next week. Book early.

8. Mutton dressed as lamb

A portion of farmed salmon costs 50p. It can be sold for £15. Alchemy? Fraud. 'To perform this miracle,' says one insider, 'indulge in a little window dressing: sprigs of watercress at tuppence each; French-sounding waiters; a Provençal menu borrowed from Elizabeth David.' Don't forget the Chilean sea bass that is actually Patagonian toothfish, or the wasabi that is actually dyed horseradish.

9. Price, quality, bollocks

For every mid-priced restaurant that deserves to die a quick, painful death, there are at least two expensive ones that deserve the same fate. Pay seventy quid for a meal so it must be good? Nope. Not necessarily. Good restaurant criticism can save you money.

10. Side-order madness

Customers in a French place down the road are invited to pay £23.95 for eight prawns. That's eight tiny Dublin Bay prawns from God knows where, with a wedge of lemon and a sprig of chervil. Would not feed a child of seven. The waiter, trained in the art of up-selling, says some accompaniment may be necessary. After paying £4 each for potatoes and vegetable of the day, the dish now costs £31.95 plus service. That's haute-cuisine prices in a mid-market brasserie. Happens all over the world.

11. The dining room as brothel

Chefs who moan about the power of critics are usually the first to send them out another appetiser, extra truffle shavings, free dessert, petits fours ... anything that might corrupt a jaded hack. Such largesse makes whores of everyone, but often does the job. 'Chefs who send out free dishes are like divorcees in fishnet tights,' says a colleague. 'You know there's something going on, but you're happy to be taken for a ride.'

12. 'Service' charge

The greatest myth of all time. A simple question: wouldn't it be nice if restaurant owners decided to pay their staff? The only other people who depend on tips to feed their kids are lap dancers. What does that tell you about the status of waiters in the restaurant world?

13. The wine list

Designed to intimidate, this leather-bound book of lies is the most amusing thing in restaurants. Sit back, relax and marvel at the audacity of comparing the aroma of grape juice to that of beetroot. Stand up and shout: 'At last! A wine that smells like boiled beets!' It's often wiser to stick to the house wines, as the mark-ups on everything else are so high.

14. What's the difference between a jeroboam and a rehoboam?

According to James Joyce, the most beautiful word in the English language is cuspidor, which is a synonym for spittoon. No one knew more about words than Joyce. His counterpart in the booze racket is Robert Mondavi, who developed a taste for wine at the age of three, after discovering that Chardonnay improves the taste of cornflakes. 'All of a sudden you enjoy your breakfast much more.' Today, the grand old man of Napa Valley is older, less feisty, but his dedication to the grape has not diminished. But, in his autobiography, Mondavi misidentified the five first growths of Bordeaux, by substituting Pétrus for Latour. When you discover that a figure of Mondavi's stature can make such an elementary mistake, you realise that wine is going to get you. It is time to dispel the myth that people who love dining out must know a lot about wine. What is the difference between a jeroboam and a rehoboam? Who cares?

15. The menu as thesis

It's dinner you're after, not Dylan Thomas. Flowery descriptions that are hard to understand can usually be translated thus: 'Watch us rip you off.' Contrary to culinary wisdom, reading a menu should not require a PhD.

16. The devil inside

Waiter and customer have a lot in common. Each lingers under the delusion that lunch is on the way, neither has more than a passing interest in the other and both are at the mercy of an ill-tempered thug in a dirty white hat who is probably urinating into a pot of mussels right now.

1.7 Malicious drinking games

In many restaurants, the majority of profits are made on what you drink. Fay Maschler, the doyenne of British critics, cites some of the pathetically obvious ruses that restaurateurs employ to inflate your bill: warm encouragement to have a drink in the bar before going to the table; pouring more wine and water after every sip; bringing petits fours that you might not want so that coffee can be charged as a separate course.

18. Fresh-faced liars

A variation on Mutton Dressed as Lamb concerning a simple beverage: orange juice. Here, concentrate is the enemy of good taste. The distance between 'fresh' orange juice and orange juice that is squeezed to order is roughly the height of the liar who sold you the former. Bring him down to size, which requires squeezing to a pulp.

19. French fiction food

Presenting an English-speaking diner with a menu in French is the antithesis of hospitality. Worse still is the fraudulent use of foreign words to describe dishes. Chefs: change 'stew' to 'daube' and double the price!

20. The well-reviewed dive

The ordinary punter is often in a better position than the critic to review a restaurant, as many critics are instantly identified and treated with special care. Hence the Well-Reviewed Dive, that plain boîte beloved of broadsheet hacks.

· Trevor White's Kitchen Con: Writing on the Restaurant Racket is published by Mainstream Publishing at £16.99. To order a copy for £15.99 with free UK p&p go to observer.co.uk/bookshop or call 0870 836 0885