They'll still have northern accents, but colloquial phrases such as "I could just fancy some cheese" are to become the far less flavoursome "I'd like a nice piece of cheese". The move has provoked the usual furious denunciation; MPs have condemned the producers, Aardman Animation. They are right that it matters, but I think they may be wrong in insisting that the northern dialect be treated as equivalent to standard English; it is too valuable for that. As usual, the reflex action is about class antagonism.
People say that we are a nation of shopkeepers; librarians is more like it. We have a genius for classification of things and people. We still use the word "class" to indicate something far more than socio-economic status - breeding, poise and taste, which show up in the way we speak. It used to be thought that someone with a northern regional accent could not have "class". Now, few people really think so narrowly. Wallace and Gromit have to think about more than what a few snobs in London say, now that they are performing on a world stage.
It's not that people hate or despise regional accents. Even the BBC is now undeterred by the prospect of a Brummie whine - a long way from the days when broadcasters such as Sue Lawley found it impossible to be taken seriously with a Black Country voice. However, Disneyfication of popular culture is increasingly forcing people to make a choice of softening their own original accents or of adopting the bland transatlantic speech that dominates the airwaves.
The drift away from regional dialects isn't about the legendary self- centredness of American audiences either. Indeed, Americans seem to find regional dialects charming; notwithstanding the difficulties of understanding the former steelworkers in The Full Monty, English accents of all kinds abound on American TV. A character in Frasier boasts a Manchester accent, and in Will Smith's series, Fresh Prince of Bel Air, the English actor Joe Marcel makes the mix more exotic by employing a posh upper-class voice that comes straight from the back benches of the House of Lords - and he is black. Difference can now be fashionable.
But should accents tell you anything at all about a person? The right answer is: "No." In reality, the answer is "Yes." In my early journalism, on the black-and-Asian current affairs show Skin, it was a vital tool. Because of the nature of our investigations, what you said to a white person might differ from what you might say to a black person. But, on the phone, how could you tell? The fact is that you can; even now I think that most black Britons can tell if the person at the other end of the line is a person of colour.
Those who grew up in the Caribbean can tell the difference between an Afro-Caribbean, an Indo-Caribbean and a Chinese-Caribbean person, with their eyes closed; the timbres are different. But all three groups speak the same language - or, more precisely, the same two languages - and this is where our friends in the north may be too hasty in demanding that their dialects be treated as universal property.
The experience of all immigrant groups is that we bring our accents to our new country, but, in order to fit in, many of us adopt the prevailing speech of the dominant majority. But when we are at home, we use our ancestral dialect. When my mother comes to visit we will spend much of the time conversing in a way virtually unintelligible to many of the readers of this column.
Perhaps the private language will become a valuable tribal symbol. Depriving slaves of the use of their private (African) languages was a vital component of their owners' strategy for preventing insurrection.
As we are forced to interact more and more often with people whom, a century ago, we would never have met, we have to find comfortable ways of communicating with them. This does not mean that the rich diversity of speech that characterises the English-speaking world will be impoverished. It simply means that every dialect has its place, and the place for some is at home, not abroad.
There's no reason to be ashamed of a northern voice, but that doesn't mean you want every Tom, Dick or Harry using it.