This could not happen in India, because we are talking about a country the size of western Europe, with 800 million inhabitants and some 14 different languages and cultures. The contrasts between one region and another are as great as those between countries in Europe. We would not expect a Glaswegian to be familiar with avgolemono, the Greek chicken, rice and lemon soup, any more than ask an Athenian to wax lyrical about haggis.
There are moves afoot in India to bring together some of the differing and delicious regional cusines. One of the pioneers is Camellia Panjabi, author of a new book on Indian food, 50 Great Curries (Kyle Cathie, pounds 20). 'People in India have little awareness of cooking which is not their own,' she explains. 'North India doesn't know what south Indian food is; they have never tasted idli (cakes of rice and white dal). They won't have eaten dosa (pancakes made of fermented rice flour and dal flour).'
Ms Panjabi discovered this as marketing head of the Taj hotel chain in India, when she sought to introduce a wider spectrum of Indian dishes on restaurant menus. She found that customers really didn't want to know. 'If people were going to eat out they wanted something special, not everyday dishes like those prepared in their own homes.'
So, in India, eating out usually means international cuisine with a French twist, or the food of the Punjab, which has assumed a national role. 'This is very strange,' Ms Panjabi says, 'since the population of the Punjab is barely one-fortieth of the whole of India. But after Partition, many Punjabis had to leave their homes, and many of them went into the food business.'
One of the tools they brought with them was the tandoori oven; in a few years tandoori chicken tikka was being sold on every street corner in India, whence it made a great leap to our own doorsteps. Ms Panjabi herself has done much to spread the word abroad; she opened an Indian restaurant in Paris, Ile de Kashmir, in 1984, and another in London, the Bombay Brasserie, in 1982.
The large, bustling, friendly Bombay Brasserie in west London was one of the first to banish the typical backdrop of wailing music and flock wallpaper and prove there was more to Indian food than a scorching hot vindaloo eaten after pub closing time, or a take-away carton of steaming red Madras curry. A Madras curry, snorts Ms Panjabi, 'in India no one has heard of Madras curry, let alone eaten it'.
She opened the Bombay Brasserie against the advice of her PR company. Bombay was synonymous with squalor, they warned her. 'They said that if we insisted on using the name Bombay, they would refuse to work for us. And they didn't'
Ms Panjabi was also consultant for Chutney Mary in Chelsea, which opened in 1990 as an Anglo-Indian restaurant. It is managed by her younger sister, Namita Panjabi, who has expanded its scope to embrace modern regional Indian cooking. You can choose dishes cooked by chefs from no fewer than five different regions, each keeping the secret of their spicing from each other.
Secrecy is part and parcel of traditional Indian cooking, as Ms Panjabi soon discovered when researching her book. In the end, it was not the chefs or home cooks who produced the magic, but private cooks who had been in the employ of rich families for generations and the cooks who prepare festive party dishes for 100 or 200 at weddings and banquets.
Using a judicious mixture of flattery and cash up front, she induced them to share their secrets, many of which involve religious practices and beliefs. The tenets of Indian cooking, Ms Panjabi explains, are underpinned by ayurveda, an ancient body of knowledge that embraces the belief that each food has special medical, spiritual and healing properties. Most high-street curries fall laughingly short of a set of rules that are carefully observed by the serious Indian cook: weighing colour, flavour, aroma and texture, balancing sweetness with souring agents.
Ms Panjabi comes from a well-to-do family in Bombay which was passionately interested in food. She read Economics at Cambridge, where she was overcome with nostalgia for the flavours of her homeland. 'I was so short of food with spices.' She concluded that Indian restaurants in Britain were only so-so, mostly manned by people from Bangladesh who had no knowledge of the variety of true regional Indian food. 'I've eaten better food than this,' she thought, and thus started a long voyage of inquiry which led to her book.
Spicing, she says, is the key to all Indian cooking. It goes without saying that she does not mean a tin of 'Madras' curry powder, but individual whole spices, heated and ground. Spices cannot be thrown haphazardly into the pan together because the properties of each are so different; coriander, the lemony-flavoured seed which is the basis of so many dishes, needs to be fried gently for about six minutes to release its flavours, while cumin, its nutty, musty-flavoured partner, should not be cooked for more than one minute or it will lose its delicate fragrance.
As well as publishing the recipes for the truly great Fifty Great Curries of the title, Ms Panjabi's book comprehensively logs the main ingredients and their roles.
Thickening agents: slow-fried onions both sweeten and thicken; yoghurt, cream and coconut milk are other thickeners; so are dal (lentils) and some nuts and seeds - ground almonds, peanuts, white poppy seeds, sesame seeds, pumpkin and melon seeds and, to some extent, mustard and fenugreek seeds.
Colouring agents: turmeric for bright yellow, saffron for pale apricot, red chillies for reddish-brown, fresh coriander leaves for green, red tomatoes for pink, dark-fried onions for deep brown, and garam masala powder for brown (when fried for one minute).
Souring agents: tomato, yoghurt, vinegar, tamarind pulp, lime and raw mango.
Spices for taste: lemony coriander seeds, nutty cumin and poppy seeds, sweet cinnamon and powdered cloves, hot pepper and mustard seeds, bitter fenugreek seeds, anise-flavoured fennel seeds.
Aromatic spices: garam masala (garam means warm, masala a spice) is traditionally a mixture of ground cinnamon, cloves, black pepper and black cardamom, though sometimes 'cooling' green cardamom is added, and bay leaf and fennel seed. Other aromatics: nutmeg, cinnamon leaf, various cardamom seeds.
Fresh herbs: hara masala (which means green spices.) Almost all recipes include fresh ginger and garlic, which are fried along with onions to start a curry. Fresh coriander leaves are used at the beginning of cooking and at the end as a garnish. Other herbs include mint, curry leaf, fenugreek leaves (bitter, an acquired taste), green dill fronds.
Chillies: India is the world's largest producer of chillies, with an annual production of some 80,000 tons. This is a subject in itself, as they vary from fresh red and green to dried chillies of every size and intensity, from mild to scorching. Used in moderation, chillies also bring out the flavour of other ingredients.
Next week: Camellia Panjabi shares the secrets of her favourite recipes: Goa fish curry, chicken pistachio, dopiaza, lamb shanks, rogan josh, and some rice and side dishes; and her book will be on offer at a special price.