There is only room for so many Walt Disneys in the world; and, to judge from the financial catastrophe of Euro Disney, that space is shrinking. The latter-day fantasist may have to content him- or herself with a playground the size of the average high street restaurant.

True, some unlikely props manage to fit through their doors. Down Mexico Way in Piccadilly, central London, fits what looks like a taxidermic horse in the foyer. The Blue Elephant in west London built a pond in its dining-room. Quite how Thai it is to have ponds in restaurants is neither here nor there; authenticity is optional in theme restaurants.

So is good food. In the case of one of London's newest theme restaurants, the Coyote Cafe, in Chiswick, I would guess that food is a necessary evil.

The owner is a Harley-riding Canadian named John Wasilko, who was inspired by the Coyote Cafe of Sante Fe, New Mexico. His appreciation was such that he borrowed the name and employed similar graphics without the knowledge of the founder, Mark Miller. This, I am assured by Mr Wasilko, is fair game. Not in my book, it isn't. But what I find truly incomprehensible is that anyone would want to emulate Mr Miller in the first place.

I met Mr Miller during his publicity tour for Coyote Cafe the cookbook (as opposed to Coyote Cafe the restaurant, now in Sante Fe and Washington DC). He wore a cowboy hat and chef's whites while he demonstrated the making of what amounted to a corn pancake, sour cream and chilli blini. Americans, he assured us, were finally rebelling against 'European linear eating' (whatever that is), the implication being that, had Britons any sense, they would reject their own traditions in favour of chilli concoctions, preferably his own bottled brands. I later learnt, during a trip through the US, that Americans are indeed rebelling - against Mr Miller's self-serving drivel.

It would appear that the Chiswick imitation of Coyote Cafe is only authentic in so far as it is bad. Before describing the meal, in which bottled Coca-Cola was the highlight, it must be said that the kitchen had not expected to cook from what it calls a south-western menu. We arrived for Sunday brunch and were referred to a blackboard menu of a couple of - dare I say? - linear offerings, such as Eggs Benedict. We were preparing to leave without eating when the waiter - one of the kindliest, cheeriest waiters in London - said the chef had agreed to cook south-western for us after all.

Nachos were a fair pile of glop, shredded lettuce, tortilla chips, avocado dip, sour cream and salsa. Green chilli chicken and corn soup tasted like something from a packet. Red chilli onion rings were flaccid and greasy, sprinkled with chilli powder; grilled swordfish was grey, tough and past its best. The waiter quickly retrieved it and adjusted the bill. Crab cakes seemed to be made from processed crabmeat, while the accompanying chilli sauce tasted like souped-up barbecue sauce. Musical accompaniment came from tape recordings of a middle-of-the-road Sante Fe radio station, including commercials.

Valley of the Kings, a new Egyptian-style restaurant, is next to the Cromwell Hospital in west London. To understand the restaurant, it helps to understand the hospital: one is more likely to see patients stepping out of a Silver Cloud than an ambulance. This is a private hospital built and owned by Arabs. It has bullet-proof glass, safes for storage of patients' jewels, and a waiting-room for bodyguards. Wallpaper is silk, taps gold-plate. At least, these were the specifications when I toured it during its construction in 1984.

The restaurant next door is approached through the brightly lit lobby of the Elizabetta Hotel, a logical residence for relatives of patients. A streetside awning suggesting a separate entrance actually leads to a bolted, lime-green kitchen door. Fellow customers on a Friday night were two large families, both Middle Eastern, solemn and extremely well-mannered. They did not look like a natural audience for waiters dressed in gear one might otherwise encounter in a crackling Thirties horror film with a title such as Curse of the Mummies.

I showed photographs of the waiters' costumes to an Alexandrian-born colleague. 'You'll have to ring the British Museum,' he said. 'It looks Pharaonic.' Alas, it is difficult to suppress a smile as the sweet waiters dash around a rather bland hotel dining-room, more or less wearing its theme on their backs.

Its owners were touting Valley of the Kings as the 'first authentic Egyptian restaurant' in London. This ignores Ali Baba, a modest and trick-free caff in Edgware, and probably several other restaurants. The owners also say their restaurant is closed at lunchtime, for the chef, Esmat Farid, spends all day preparing his intricate dishes. Of these, my companion and I loved what she called 'the stuffed stuff'. A large platter called Valley of the Kings contained delicious stuffed baby marrow, tomatoes and bell peppers. Main courses were less pleasing. One of four different lamb tagines on offer was tough, its tomato liquor bland. Grilled baby chicken, which had been marinated in mustard, lemon and spices, was good. In places, it was also close to raw.

Desserts were so exotic as to be somewhat unapproachable; one an intriguing custard, another that tasted like cornflakes and nuts. If there is a craze one would hope might catch on in London, however, it is for Egyptian fruit drinks. Tamer hindy tastes of date and tamarinds, strange but wonderful to a Western palate. Karcadeh, an intense red tea perfumed with what tasted like hibiscus, was perhaps too sweet, but astonishingly good.

As theme restaurants go, Valley of the Kings seems to be selective, designed for an exclusive expatriate community and the families of patients of the Cromwell Hospital. The attempt to sell it to a wider market appears to have been a rather inappropriate afterthought.

Coyote Cafe, 2 Fauconberg Road, London W4 (081-742 8545). Drinks and bar snacks from pounds 5; meals pounds 15- pounds 20. Open Mon-Sat 12noon-11pm (last orders 10.30pm); Sun 11am-3pm brunch menu only. Major credit cards except Diner's.

Valley of the Kings, Elizabetta Hotel, 162 Cromwell Road, London SW5 (071- 370 4282 or 071-835 0388). Meals approximately pounds 20- pounds 30. Open 6- 10.30pm (last orders); hours vary during Ramadan. Major credit cards.

(Photographs omitted)