It's become a staple of the British culinary landscape, an exotic blast from the subcontinent that has long supplanted the fish-and-chip shop as the nation's favorite eatery.
But 40 years after it brought papadums and vindaloo to the conservative British palate, the curry house is feeling the pinch. No, it's not the food, which remains consistently yellow and still lures 2.5 million customers into around 12,000 restaurants every week. Neither is it a sudden health warning about the perils of mango chutney.
No. The problem facing Indian restaurants (called that even though the vast majority are Bangladeshi-run) is a labor issue. To coin a phrase, these days you just can't get the staff.
New immigration rules gradually being rolled out here give curry houses highly restricted scope to employ chefs, porters, and waiters from Bangladesh. Now, there are some 27,500 unfilled vacancies in restaurants up and down the country.
"We are suffering, our business is going down," says Baljoor Rashid, who owns a chain of 15 restaurants in southeast England. "There is a shortage of waiters, a shortage of chefs, and a shortage of unskilled kitchen porters."
As a result, he says, an industry that turns over £3.5 billion ($6.9 billion) a year and employs 90,000 people, most from the subcontinent, is at risk.
"There are a lot of restaurants closing already," says Mr. Rashid, who is president of the Bangladesh Caterers Association. "Because of the shortage of staff, restaurants are dying."
The government changed tack on immigration after hundreds of thousands of east Europeans flocked to Britain in the wake of European Union expansion in 2004, a mass migration that one expert described as "the largest-ever single wave of immigration the British Isles have ever experienced."
To compensate, a new points-based system for immigration aspires to regulate migrant numbers. But the crucial category for Bangladeshi restaurants – low-skilled workers – is unlikely to be opened for several months because the government feels it has enough of such migrants from Eastern Europe. "It's a category which will be there to fill specific temporary labor shortages, but at the moment it's not required," says one Home Office official, on customary condition of anonymity.
Rashid says this has resulted in the culturally absurd situation where the government is urging Bangladeshi kitchens to employ Polish staff.
"We went to see the immigration minister Liam Byrne," he says. "He told us we have to use East Europeans. We said we have tried them but it's impossible. Firstly, how can they work in a Bangladeshi kitchen when there is the language barrier?
"No. 2: People have to understand the culture to provide the authentic curry."
Nowhere perhaps is this shortfall more keenly felt than around Brick Lane, the heart of the Bangladesh community in London's East End. Here, Muquim Ahmed, owner of one of London's best Bengali restaurants, Café Naz, is desperately casting round for kitchen porters prepared to do the unglamorous behind-the-scenes work at one of his five outlets.
"I've tried people from Poland," he sighs. "They work for a week and they don't turn up the next week. I think they don't like the smell. Indian food tastes good, but in the kitchen it smells awful."
He says British customers must expect restaurants to close. "The problem in the kitchen won't be reflected in the front of house," he says, but if the crisis continues "slowly I'll give up my five remaining restaurants. I'll shrink and shrink and in five years I'll be gone."
Enam Ali, owner of the award-winning Le Raj restaurant near Epsom Downs in southern England, says he is struggling to retain high standards with only 10 staff where he used to have 16. Staffing has become so critical that he is increasingly pitching in himself. "People drive 50 or 60 miles to come to my restaurant, and if I don't give the right service, I'm going to lose business," he says.
As for employing Europeans, Mr. Ali shrugs at the idea. "We don't mind, but customers say they don't want to see any other nationality. They want to see Indian people running Indian restaurants."
The Immigration Advisory Service, a charity that advises on immigration law, has taken up the case, telling Mr. Byrne that he must think again. IAS chief executive Keith Best says the effective moratorium on low-skilled workers from non-EU countries could do "irreparable damage" to curry houses.
"For many low-income families the only chance they have of eating out is to go for a curry," he says. "The minister thinks that the vacancies in the curry industry can be filled by Eastern Europeans who have no cultural sensitivity towards or understanding of the curry industry.
"It is a sad comment on government policy that it favors Eastern Europeans over citizens of Commonwealth countries such as Bangladesh whose preceding generations have contributed so much to the British economy and continue to do so."
Byrne has responded by saying that the Migration Advisory Committee, a panel set up in 2006, would look into the matter. It remains unclear how many committee members enjoy a good curry.