Richard Bilton:"Half the dishes tested contained excessive additives"

Most diners think the worst consequence of eating spicy food is a touch of indigestion, but although Britain's most popular dish can be coloured by spices alone, many restaurants are falling back on artificial colourants to make their curries look more appealing.

A trading standards swoop on restaurants in the West Midlands, known as Britain's "Balti Belt", found that more than half of the most colourful dishes contained levels of additives that would breach safety rules under some circumstances.

Repeated overexposure to the colourings - Tartrazine, Sunset Yellow and Ponceau 4R - are thought to lead to increased sensitivity to allergies and even the onset of asthma.

Current legislation covering the use of colouring applies only to sauces, not to meat or rice.

Meat inspection

The Midlands Co-ordinating Group on Trading Standards surveyed dishes in which the meat is normally marinated to give it colour, such as tandoori and tikka masala.

Too many curries had too many additives, experts found

Some dishes contained colouring levels up to 16 times that permitted by law in a sauce.

Sandwell Council, which headed the inspections, will be pressing for changes to the law to include coloured meat and rice.

Roger Horton, the chair of its environment committee, said: "Consumers believe mistakenly that the brighter the colour, the hotter the dish.

"Twenty-one meals were found to have no added colours - tomato powder, red chillies and turmeric provide sufficient colour for an authentic Indian meal."

Some restauranteurs were in agreement with the council's action.

'Public don't realise'

Mohammed Aslam, who manages a chain of seven "colour-free" curry houses, said many British curry fans did not realise how much colouring was being used.

He said: "It would be safe to say a lot have never seen an Indian-style kebab cooked without food colour.

"That's how they have been introduced to the food and they think that's how things are supposed to look.