The curry, spicy and steaming hot, eaten with naan bread and cold beer, has been popular as a takeaway or a late-night meal for the British.
But restaurateurs are in a sweat about the future of the industry, which this year celebrates its 200th birthday, after the government introduced tough new immigration rules that threaten the influx of chefs from abroad.
Ever since officers of the British Empire brought home the spices and dishes of south Asia, Britons have embraced the curry -- a name used to describe a wide variety of food from the region -- while adapting it along the way.
This included inventing the chicken tikka masala, a lightly-spiced, creamy, tomato-based stew proclaimed as a "true British national dish" by then foreign secretary Robin Cook in 2001 and which now sells 49 million portions annually.
But the industry still relies on foreign cooks, largely from Bangladesh -- and it is warning that a cap on non-European Union immigration introduced on July 19 by Britain's new coalition government has put its future in jeopardy.
"Cooking curry is a special art," said Bajloor Rashid, president of the Bangladesh Caterers Association, which represents 12,000 Bangladeshi restaurants employing 100,000 people directly in Britain.
"You just cannot have anyone from here or there and becoming a chef -- they have to enjoy the cooking, they have to have the art of the cooking, otherwise it's not going to work."