More than half the curry houses tested in a trading standards survey were using illegal levels of three potentially harmful colourings in chicken tikka masala.
The study, on behalf of Surrey trading standards department, showed that of 102 curry houses tested, only 44 kept their use of colourings within legal limits. One restaurant was found to be using four times the legal limit in its dish, reports Timesonline.co.uk
Harsh artificial colourings in chicken tikka masala, the nation's favourite dish over even fish and chips and shepherd's pie, have been found by trading standards officials "at illegal and potentially dangerous levels".
Chicken tikka masala, a mild curry dish in an often extremely sweet tomato-based sauce, is cooked in a charcoal-fired oven, and served an estimated 23m times a year in Britain's 9,000 curry houses. Millions eat packaged equivalents from supermarkets - Sainsbury's alone sells 32,000 packs a week and the flavour also finds its way into foods such as pizzas and crisps.
Its exact provenance remains cloudy, but legend has it that an enterprising Indian or Bangladeshi restaurant owner in Britain added a fluorescent sauce as "gravy" because that is what a demanding customer wanted.
But the warnings of health risks from tartrazine (E102), sunset yellow (E110) and ponceau 4R (E124) were challenged by the government's Food Standards Agency, which insisted "the available evidence - has not identified particular harmful effects , even at very high intakes, and has not shown a link to cancer risk".
Natural ingredients such as turmeric, saffron and paprika should provide all the colour necessary.
Tartrazine, also used in products such as cakes, fruit squash and sauces, has been linked to allergic reactions, particularly among those intolerant to aspirin, as well as those suffering from asthma. It has been used by egg producers in chicken feed to make the yolks more yellow. Though common in the UK, it has been banned in Norway and Finland.
Mr Chapman said tikka masala could be prepared using paprika, chilli powder and tomato puree, all red ingredients. "It is rather nice. Adding tartrazine is unnecessary. It is tasteless," according to Guardian.co.uk