When non-whites do appear in dramas and soaps, they are often "token" characters who are stereotyped as Asian shopkeepers, such as the character Dev in "Coronation Street", and black single mothers like Denise in "EastEnders". The study was commissioned by Channel 4 following the "Celebrity Big Brother" race row last year when Jade Goody and glamour model Danielle Lloyd rounded on Indian film actress Shilpa Shetty.

Commission chairman Trevor Phillips says all the evidence shows that television was still "hideously white where it matters", a reference to those in senior roles. "Most ethnic minority participants felt the media had a responsibility to reflect Britain's diversity across all genres and was failing to do so in three main ways: by relying on tokenistic and stereotyped representation of characters; by representing extreme and exaggerated characters; and by failing to reflect the realities of contemporary ethnic minority culture."

Asian and African viewers also say they are concerned that white viewers get the wrong impression of ethnic minority groups because they are often inaccurately portrayed on screen. One Indian woman tells researchers: "We would like to see a more realistic view of Asians. A lot of Asians are professionals and educated and we don't just work in corner shops."

Muslim respondents say that a recent episode of "Wife Swap" featured a Muslim family where the mother was "completely over the top", while Asian dramas often focussed on arranged marriages.

The research comes only weeks after Samir Shah, a non-executive director at the BBC, accused broadcasters of rampant tokenism in their programming, The Telegraph points out.