originally published in The Daily Mirror on 23 October 1975 and presumably the following week also

I do love this genre of social observation / commentary that is thought through but not necessarily based in research or any kind of scholarly proof. I would love to get hold of old issues of New Society for instance (well, the contents of that were probably pretty rigorous, given the number of academics who wrote for it, but it's not written up as articles in a scholarly publication - more in the style of a newspaper column). I particularly like observations and predictions that have been overtaken by time. 

But this one by Waterhouse seems pretty on the money - seems to point to what you might call the GLC / City Limits class, which then actually had a belated if unsuccessful shot at power with Corbyn. Perhaps what hobbled it was the very split that caused Time Out and City Limits to break into two, with Time Out going the path of yuppie / gentrification / the reaffirmation of the old class lines. Although that said, even that Time Out constituency votes Labour I'm sure - London now is a Labour city-state. Labour in the metropolitan form is a tribal identification based on progressive values and even aesthetics, as opposed to an identity based around the workplace, being in a union etc.

As suggested by Stylo in comments, another - more hostile - take on the Polyocracy came from Malcolm Bradbury with his novel - later TV series - The History Man.