Over a quarter of takeaways are illegally using high levels of artificial colourings to make "delicious" curries rather than using turmeric or chilli powder, a survey by Trading Standards officers in west Yorkshire revealed.

One Indian takeaway was found to have used over five times the legal amount. The survey was conducted by sampling the same curry, chicken tikka masala, at each takeaway.

Of those tested nearly all contained a cocktail of the colouring agents Tartazine (E102), Sunset Yellow (E110), Ponceau 4R (E124), Carmoisine (E122) and Allura Red (E129).

The Food Standards Agency has called for the colourings to be phased out, saying they are a potential cause of problems such as hyperactivity in children and skin rashes in adults.

As per the law, a curry sauce may not contain more than 500 milligrams of artificial colouring per kilo.

West Yorkshire's Chief Trading Standards Officer, Graham Hebblethwaite, said: "The FSA is asking food and drink manufacturers to phase out the use of these artificial colours, but the message does not appear to have been heeded by the takeaway curry trade."

Mohammed Aslam, who manages a chain of 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. Indian cooking doesn't need artificial colouring because you can create the colours you want with spices."

He added that Indian restaurants should stop this practice "for the sake of our industry."

Spices which add colour are paprika (light orange), mustard (yellow), turmeric (yellow) and cumin (brown).