Yet now its popularity is such that noodles are being feted as the food of the Nineties. Wagamama plans four more London branches plus one in Paris, and maybe even one in Japan. Judging by the lengthy queues outside the Bloomsbury basement premises every night and at lunchtime, the demand for stir-fry noodles and noodle soup is insatiable. Despite speedy service, and a daily tally of 1,200 meals (400 lunch; 800 dinner) a day, Wagamama can hardly cope with demand. 'We are losing customers because of the tailback,' says marketing manager Pauline Price.
One night last week a constant 50-strong queue seemed remarkably placid as they lined Streatham Street. Only one out of 20 arrivals departed. Another looked doubtful but a young man who was just leaving chirped consolingly at him: 'It's OK. It moves amazingly quickly.' And it does. After 10 minutes you have a drink in your hand as you wait on the stairs, 10 minutes after that you sit down to a vast bowl of steaming noodle soup, costing pounds 4.50. The chefs get through 100 kilos of noodles a day.
The restaurant's success stems from more than just an increasing desire among Westerners for Japanese food. The first Japanese restaurants in London were set up in 1969 and still suffer from a traditional British suspicion of raw fish. Wagamama's success is due to a skilful Westernising of the food on offer; and what Mog Morishima, 29, design director of Wagamama Ltd, calls, rather blushingly, 'the creation of a post-modern culture in eating'.
'It was quite obvious to us,' he says, ('us' being the four bright twentysomethings - two English and two Japanese - who formed Wagamama Ltd in 1992) 'that there was a gap in the British market. Anybody who had lived in Japan would have recognised it instantly. Apart from a need for good, cheap, healthy fast food, the British had not yet developed the concept of commercial design. Wagamama is supposed to be more subliminal than McDonald's - the concept is far more complex than the red- and-gold arches.'
The design is minimalist. Customers sit at long wooden tables and benches like students in their college dining- room. In fact, so many are students it easily could be a college dining-room. The few 30- plus oldies, especially those in pin-stripes in the evening (at lunchtime it is acceptable), squirm uncomfortably.
The new Wagamamas will look different though. 'We want to destroy the idea that fast-food restaurants need to be generic,' says Mr Morishima. Details and locations are still secret, but the likely areas are studenty neighbourhoods such as Notting Hill or Camden.
One fixture is the hi-tech computerised ordering system, largely responsible for the quick turnover - the average time per meal is 45 minutes. The waiters punch your order into a machine that resembles a calculator and it is logged straight into a terminal in the kitchen.
Only 5 per cent of the clientele is Japanese. 'We are different from the other ramen bars in London,' explains Mr Morishima 'because we have westernised our food to a certain extent - although the core is Japanese. Real Japanese ramen, though, is made with pork stock and is quite fatty, whereas we use chicken stock; our noodles, too, are different.'
Wagamama may well be the only restaurant in London to include on its menu details of a Japanese management technique widely used in industry. Their 'kaizen' philosphy aims for continuous improvement and comes from listening and adapting to staff and customers. Examples are the questionnaires available for the queueing masses and a medley of international chefs are employed 'for inspiration'. Kaizen also operates in subtle ways. All the 60 staff wear Aids- awareness ribbons and there is a basket of them at the entrance. 'When we opened we had a lot of gay customers,' explains Mr Morishima. 'It is part of our young post-modernist outlook; actually it's also a way of saying thank you.'
Evidence of wider noodle- mania is growing. Wagamama's expansion follows the opening last year of Europe's first Japanese superstore, the Yaohan Plaza in Colindale in north London. In a few hours last Sunday pounds 6,000-worth of noodles were sold - and many customers were not Japanese.
As Rory Ross of Tatler puts it: 'Noodles are the food of the Nineties. They are far more politically correct than chips (no class connotations); they are healthier; less labour-demanding (no chopping); and - best of all - you don't have to wash up knives and forks afterwards.'