The post-colonial Anglo-Indian dish chicken tikka masala was apparently invented in Glasgow in the early 1970s, while balti cuisine was introduced to Britain in 1977 in Birmingham. In 2003, there were roughly 9000 restaurants serving Indian cuisine in Britain. The majority of Indian restaurants in Britain are run by entrepreneurs of Bangladeshi (often Sylhet) and Pakistani origin. According to Britain's Food Standards Agency, the Indian food industry in the United Kingdom was worth £3.2 billion in 2003, accounting for two-thirds of all eating out, and serving about 2.5 million British customers every week. Indian restaurants typically allow the diner to combine base ingredients — chicken, prawns or "meat" (lamb or mutton) — with curry sauces — from the mild korma to the scorching phall — without regard to the authenticity of the combination. The reference point for flavour and spice heat is the Madras curry sauce (the name represents the area of India where restaurateurs obtained their spices, rather than an actual dish). Other sauces are sometimes variations on a basic curry sauce: for instance, vindaloo is often rendered as a fiery dish of lamb or chicken in a Madras sauce with extra chilli, rather than the Luso-Indian dish of pork marinated in wine vinegar and garlic, based on a Goan Portuguese dish "carne de vinha d'alhos".