First Night: Midsomer Murders, ITV

Dark deeds as usual in all-white rural 'bastion'

"I did like that Mr Barnaby... but, well, he wasn't one of us, was he?" They don't much care for outsiders in Midsomer Murders, as we've recently learnt – but it was oddly gratifying to find xenophobia ingrained in the script of the first post-scandal episode from the very beginning. The speaker was the headmistress at a private girls' school, and Mr Barnaby, of course, was DCI Tom – still suspect even after 14 years in the post. Now he's made way for his cousin John, played by Neil Dudgeon as a drily sarcastic type with a sprechhund, an attentive terrier who acts as a silent interlocutor when there's no one else around.

I thought Neil Dudgeon did very well, given the raw material he was working with, but I don't suppose he'll be getting a lot of attention on his first outing. Most viewers will have been far too busy playing Hunt the Little Englander. The headmistress was very promising: "I do not want my girls contaminated by the dross that crawls out of that estate," she said grandly – thus revealing to us a fact that I hadn't previously been aware of, which is that Midsomer has a council estate. Those who like to think of themselves as manning the last bastion will be glad to know that it too had been ethnically cleansed.

An enterprising newspaper claimed to have found a black face in last night's episode, after a lot of work with the DVD pause button. But I confess I missed it completely. The closest we got was someone talking black – or at least a ludicrous gangsta parody of black speech. "Yo, yo... whassup ma bitches," said Dave "Dogboy" Day, a Tim Westwood-style DJ who (and you may need heavy lifting gear to suspend your disbelief here) had been invited to help to judge a vintage car rally to be held at the school. "Oh my days!" he exclaimed as he cruised up the drive and spotted a recent conquest, "you're still in school, innit!" Sadly, even pretending to be black doesn't go down very well in Midsomer. He barely survived one ad break before he was pierced through the chest by the crank handle of someone's classic car – even under the new staffing arrangements the series maintains its commitment to baroque extermination.

The episode ended with a wildly complicated pulley-and-ploughshare arrangement to do away with DCI Barnaby, which allowed him to have one of those leisurely tidying-up conversations with the killer and – more importantly – enough time for his sidekick to drive in from town and save him.

Some have suggested that the hip-hop DJ would have been a perfect role for a black actor – and that his presence in this episode undermines Brian True-May's suggestion that realism alone was guiding his casting choices. But the real question is whether any decent black actor would have wanted a role so ludicrous. Midsomer Murders is Enid Blyton for grown-ups, Famous Five characterisation sprinkled with a bit of incest and sexual adventure. And I know actors have to eat and pay their mortgages, but it's hard not to feel that in bringing apartheid to the English village, True-May has spared black and Asian performers an unwelcome humiliation. If the series had included them – and represented them with the same broad-stroke caricature as it doles out to nubile schoolgirls, middle-class men and affection-starved teachers – then it's possible the result would have been even more offensive than their exclusion.

Anyway, one heartily wishes Neil Dudgeon had material more worthy of his talent, but his talent is obvious none the less, and his character appears to be a prodigy of unshowy cerebration. He solved this crime – it seems – simply by close study of the covers of vintage Motor Sport magazines, which bodes well given how busy he's going to be over the coming series.