'FEEL like popping out for an Indian tonight?'. . . 'Feel like a Chinese?' So hackneyed have these refrains become that they almost merit entries in a dictionary of phrase and fable. But, it seems, lazy cooks are increasingly touting a new type of invitation. 'Feel like a Thai?'

A Mintel survey, published last week, reveals that the British spent over pounds 18.5m on Thai food last year.

As recently as five years ago Thai food was the height of obscure culinary chic. But now Thai restaurants are popping up everywhere. Edinburgh has three, Manchester five, while London has round 350. Even Banbury and Oxford harbour one or two. There are probably around 500 in Britain altogether, but it is estimated that there will be five times that number in a year's time.

Thai food has even found its way into pubs. Between tubs of coleslaw and sweating pork pies in the chill cabinets, sticks of beef and chicken satay can be spotted with increasing regularity. Imperial Hotels are about to introduce a complete range of Thai snacks, including dumplings, spring rolls and sesame toast, to serve alongside the peanuts and crisps.

The story in supermarkets is the same. Sharwoods, the market leaders in ethnic condiments, added Thai sauces and soups to its list just three years ago, and report they now represent 10 per cent of their output. Asda launched its new Thai range last November, and, at Marks & Spencer, Thai-style food is doing nearly as well as its popular Coronation chicken.

'Food tastes are changing fast,' says Jeffrey Hyman, of Sharwoods. 'In the old days it might have taken 20 years for food types to move from, say, London's Chinatown out into the provinces. Nowadays it is more like 20 weeks.'

So what has happened? One explanation is that there are many more Thai cooks in this country than there once were. Recent Home Office figures show a threefold increase in the number of Thais working here compared to ten years ago. In 1982 just 17 Thais were given work permits. By 1992 there were 70. Hyman thinks that it is the novelty of Thai food that has made it so attractive to the British. 'You have roughly 8,000 Chinese, and 8,000 Indian restaurants in this country - that's nearing saturation point. The British want something new to eat.'

In response to what they recognise as a new hot seller, many Chinese restaurants have started repackaging themselves as Thai. Unless you go and poke your head round the kitchen door it might be difficult to tell the difference. (Thais tend to focus more on using fresh herbs - lemon grass, galangal and fresh chili, than their Chinese neighbours.)

One of the first great pioneers of Thai food in Britain is Thai restaurateur Mudita Karnasuta. In 1970 she set up the Siam restaurant off London's High Street Kensington; by 1980 her family owned three more in Chelsea.

Two years ago she moved to Sussex where she bought the freehold of a country pub with her partner, Suhail Hussain. Once called the Hamilton Arms it is now called the Hamilton Arms/Nava Thai Restaurant.

'I saw the possibility of creating a unique set up,' Ms Karnasuta explains. Unique it certainly is. The interior of the pub is divided into two. On one side is Mr Hussain, who despite being born a Muslim in Kashmir serves drinks behind the bar. On the other there is a full- scale Thai restaurant, with a Buddah in the corner, bedecked with Thai woodcarvings and hanging baskets. Thai snacks are served at the bar, and full meals in the restaurant.

The fact that Thai food is a hybrid between Indian and Chinese food - two of the best loved cuisines in this country after our own - explains its success. Fiona Harris, marketing manager for Imperial Hotels says, its eclecticism is what makes Thai food so enticing. 'Like Greek food you can eat as much or as little of it as you like,' she says.

Thai food is a snacker's delight. Thai canapes have become a popular alternative to bowls of peanuts at up-market drinks parties: delicately presented pouches of filo pastry; prawns spliced like exotic flowers; pandana leaves folded round nibble-sized chunks of chicken - are all calculated to allow one to stuff down large quantities without realising it.

Thai food is also being marketed as a healthier than some of its ethnic cousins. Most Thai food is whisked round a wok rather than deep-fried, and is free of the gluey texture characteristic of many Chinese dishes, or the wells of vegetable oil in Indian.

'Many people find Indian curries are too spicy, whereas the advantage of Thai food is that it caters for every palette,' Harris says. 'It ranges from extremely hot and spicy dishes like Tom Yam Kung prawn soup, which most Westerners can't eat, to the mild dishes, like fish in galangal and coconut cream.'

Keith Floyd, the TV chef is a self-confessed Thaiophile, and admires the 'culinary piracy'of the Thais. Throughout history, he explains, they have taken the best aspects of various Eastern cuisines; most notably Chinese and Indian food, and melded them together. Floyd regularly has Thai food on offer in his Devon pub.

Not only are there more Thais coming to Britain, but there are more Britons going to Thailand: in 1986 around 100,000 took a Thai holiday; last year the figure was nearer 250,000. 'It's become to the British what Malaga used to be five years ago,' says a spokesman from Kuoni travel agency. Perhaps it is only a matter of time before bars selling bangers and mash, burgers and steak and kidney pie spring up all over Bangkok.

(Photograph omitted)