The producer of one of ITV1's best-known crime dramas, Midsomer Murders, has been suspended from his job after he suggested in an interview that there was no place in the programme for ethnic minorities and it was the "last bastion of Englishness".

Brian True-May, the co-creator of the show which began on ITV in 1997, said the series "wouldn't work" if there was any racial diversity portrayed in the sleepy village life of the fictional county of Midsomer.

Production company All3Media has suspended True-May while it conducts an inquiry and an ITV spokesman said the broadcaster was "shocked and appalled" by his comments.

"We just don't have ethnic minorities involved. Because it wouldn't be the English village with them," True-May said in an interview with the Radio Times. "It just wouldn't work. Suddenly we might be in Slough ... We're the last bastion of Englishness and I want to keep it that way."

An ITV spokesman said: "We are shocked and appalled at these personal comments by Brian True-May which are absolutely not shared by anyone at ITV.

"We are in urgent discussions with All3Media, the producer of Midsomer Murders, who have informed us that they have launched an immediate investigation into the matter and have suspended Mr True-May pending the outcome."

True-May was speaking to the Radio Times in advance of the new series of the drama, which returns to ITV1 next week. Originally based on the books by Caroline Graham, Midsomer Murders has so far featured 251 deaths, 222 of which were murder.

The show's original star, John Nettles, previously best-known for his title role in another long-running crime drama, BBC1's Bergerac, appeared in the last of his 82 episodes last month. He will be replaced in the leading role by Neil Dudgeon playing John Barnaby, the cousin of Nettles' original inspector Tom Barnaby.

Perhaps anticipating criticism of his comments, True-May admitted: "Maybe I'm not politically correct ... I'm trying to make something that appeals to a certain audience, which seems to succeed. And I don't want to change it."

The race equality thinktank the Runnymede Trust said True-May's comments were out of date and no longer reflected English society.

"Clearly, as a fictional work, the producers of Midsomer Murders are entitled to their flights of fancy, but to claim that the English village is purely white is no longer true and not a fair reflection of our society, particularly to this show's large international audience," said the trust's director Rob Berkeley. "It is not a major surprise that ethnic minority people choose not to watch a show that excludes them."

True-May has also banned swearing, graphic violence and sex scenes from the show, but his idyllic formula does not stop challenging storylines or other elements of diversity which do not involve ethnicity.

"If it's incest, blackmail, lesbianism, homosexuality ... terrific, put it in, because people can believe that people can murder for any of those reasons," he said.

Not all of the programme's cast appeared to agree with the programme's producer. Actor Jason Hughes, who plays sidekick DS Jones and starred as Warren in BBC2's This Life, said: "This isn't an urban drama and it isn't about multiculturalism. That's not to say that there isn't a place for multiculturalism in the show.

"But that's really not up to me to decide. I don't think that we would all suddenly go, 'a black gardener in Midsomer? You can't have that'. I think we'd all go, 'great, fantastic'."