First, be polite to your trolley

Yo! Sushi is a fantasy of The Restaurant of the Future that could have been designed and directed by Jacques Tati. Under banks of chromium- plated downlighters little colour-coded saucers of lurid sushi, each capped with a little plastic dome, snake round and round the bartop on a conveyor belt of stainless steel discs, cooks chop and slice and feed robot rice- compressors in chromium display pens, the white walls are flooded alternately with lime green and pink light, pop music thuds in the loudspeakers, and the Diners of the Future sit in rows at the counter, some talking into mobile phones, but most of them blankly poking tiny packets of rice and raw fish into their mouths with wooden chopsticks.

There are also pale-wood tables for four, with metal benches, each table having its own chromium-plated tray with a square jar of sliced ginger, a pot of tangy wasabi (made from a type of horseradish), a bottle of soy sauce and a paper napkin dispenser, and at the end of each table there is a water-tap with a stack of glasses.

We had supper there four days after it opened, and it was already packed. Yo! Sushi does not take reservations, so you wait behind a crush barrier at the door, say how many you are, and the Head Waitress of the Future, crop- headed and wearing a plain black shirt and trousers, lifts her arm in an alarming signal based on the Nazi salute and bellows some-thing incomprehensible above the din of the music to an orange-shirted colleague at the other end of the restaurant.

He bellows back what was probably an estimated waiting time, and you are then taken in, already hypnotised by the snaking plates of luminous food and the eerie chromium-plated drinks trolley gliding along apparently of its own volition. At your table, or at the bar, you are given a bright-blue plastic-covered "sushi identifier" with 20 little colour illustrations of what is gliding by under the plastic domes.

This brochure also contains historical notes in very small print: sushi means a sandwich and was invented 2,000 years ago, the sushi conveyor was invented in 1968 by Egawa Kinsho, tuna can swim at speeds of up to 50-miles an hour even when asleep. Japanese and "Icelandics" who eat raw fish "live lives longer than many".

By this time I was beginning to get a bit irritated by the conveyor belt: whether or not Egawa Kinsho was inspired while waiting for his luggage at Tokyo airport, there is the familiar sense of futility as the same little package comes past for the seventeenth time, and even something of the desperation of when Ian Carmichael's bowler hat falls onto the conveyor belt in I'm Alright, Jack to be covered with chocolate and automatically fitted with a cherry.

Conversation was impossible. My Italian guest did his best, impressing us with his wonderfully fluent use of English, which included the words "robotic" and "restaurant of the future", but it was a losing battle against Rod Stewart's "Sailing", some mad harpie sing- ing "My Guy" and more modern works of a rather less elevated nature.

We were brought little bowls of miso soup, poured ourselves glasses of water, ordered warm sake and Sapporo beer, and plucked up enough courage to start taking things off the conveyor belt. Our Italian guest had in the meantime quizzed the waiter in the orange shirt about where the fish came from - the tuna is flown up from South Africa, the salmon from Scotland, the white fish bought every morning from Billingsgate - and what we had was absolutely fine. I found it difficult from the illustration to tell whether I was eating raw salmon, saka, or fatty tuna, toro, but something of that colour came past again and again. Mackerel, saba, we decided was better, as it was cut in thicker slices and came without rice, but that turned out to be as long coming on the conveyor belt as your own suitcase and in the end we asked the waiter to bring us some by hand.

On the board explaining the colour coding - lime green pounds 1, turquoise blue pounds 1.50, purple pounds 1.80, orange pounds 2.50 or pink pounds 3.50 - there were also specials, and we asked the waiter for two sea-urchin sushi - very good - and two salmon-skin rolls, which were warm and a little more comforting than the sushi, that couldn't really be said to make a meal, though I'm sure in the future they'll think of it as a banquet.

At that moment we tried to engage the robotic drinks trolley for more sake. It absolutely refused to stop, but I managed to snatch a half-bottle and two more cups as it went by. This turned out to be stone cold, and as there wasn't much you could say to a robotic trolley, I decided to put it back.

There was then a genuinely Tatiesque episode. One of the waiters, turning a corner too fast and swerving to avoid the robotic trolley coming the other way, dropped a bowl, which smashed on the floor. The waiter immediately vanished, ducking under the moving foodway and into one of the chromium pens. The conveyor belt of bright food snaked on, the music thumped, the diners at the bar poked their faces and listened to their mobile phones unheeding, and the waiter in the orange shirt came over and actually knelt down to pick up the broken pieces in his fingers. For a moment it was real life. Then the waiter in black who had dropped it reappeared through the little chromium hatch, swinging a chromium dustpan and brush, flick, clang and then suddenly everything was back to normal.

It's a great fairground ride, a snack in the Pavilion of the Future. Tipping is forbidden, we ate quite a lot of sushi - the waiter totting up the bill with his thumb from the colours of the empty saucers - and the bill for two with drinks came to pounds 30.05. All the same, it was a relief to slip into an Italian caff just round the corner afterwards for a sticky bun, a cappucino and a proper talk.