We are all Downtonians now. In a recent televised speech, union leader Frances O'Grady warned that the UK was turning into Downton Abbey. This was interrupted, without irony, by some royal baby news (he'd killed again, I think). The world of Downton Abbey has not, as I once predicted, led inexorably to Downton Soviet. I should really have noted the "baron" at the front of its creator's name. Baron Julian Fellowes might as well have been named Toffy Toffington and his programme, Oh What a Lovely Class System.

For some, it’s not so much a period drama as a lost idyll/ future utopia. Historical facts are treated pretty casually. Characters are endlessly referring to the fact that the world is changing and are suspiciously prescient about the future. “Oh, tis a new era,” sighs Daisy the scullery maid, while ironing a fresh copy of Buzzfeed for his lordship. “Soon, we’ll have the second World War, hydrogenated fat and the iPhone 6.”

Despite this fetish, change actually happens slowly on dozily soapy Downton. After a few notable deaths (whatshisname, for example), the mainstay characters are still there, in roughly the same positions orbiting familiar plots. The dowager countess continues to wink at the camera while looking like, and possibly being, a supercilious meerkat (Downton Abbey = Meerkat Manor?). Lady Mary (aka Downton Julie Brown) is, as ever, a sulky posh vapour who is fatal to men, while lady Edith has given her secret child to peasants (it'll be bossing them around in no time, given its superior breeding).

Possible sources of rebellion have been house-trained. Brother-in-law Tom – or "Uncle Tom" as he is known to his nephew and Irish people – was originally a republican/socialist Punch cartoon, but he has since realised that he loves the English class system. In the new series, I expect, his features will get ruddier and he'll start dressing like a pearly king. Nefarious under-butler Thomas will also give in to destiny and start sporting a cape, top hat and twirly moustache.

Elsewhere, Bates the valet is still transitioning into a doleful basset hound. It's his job to dress lord Grantham. Grantham doesn't think it's weird that a grown man dresses him. But if something happens to Bates, trust me, there'll be some dressing-himself accidents and it'll be shellsuits and onesies for his lordship for the rest of the series. Bates is regularly suspected of crimes he did not commit, like Eccles the border terrier in Coronation Street.

Carson the butler is the most loyal retainer and a protector of the old ways. He would give Grantham a kidney if Grantham suddenly decided he wanted three kidneys. And if Carson injured his hoof and needed to be put down, Grantham would do the deed himself. “Goodbye old friend,” he’d say, raising the shotgun to Carson’s temple.

Sometimes in Downton the lower orders attempt to improve themselves (uppity flibbertigibbets) and middle class do-gooders like cousin Isobel say things like: "Why must the servants toil so, while we live in luxury?" Grantham then picks her up by the lapels and shouts "Because it's lovely."

This is usually followed by shots of gleaming cutlery and shiny bells and a happy maid laughing consumptively.

There will be more of this sort of thing, because Fellowes disapproves of impolite agitation. Historical change, a la Downton, happens in a context-less flurry of baffling costume changes, pub quiz factoids and noblesse oblige.

Actually, I'm no longer even convinced Downton is about history. I'm worried that in the final episode David Cameron will appear and it will be revealed that the programme isn't set in the past at all, but in his house, last Wednesday. "Surprise," baron Julian Fellowes will say.

Then they’ll both laugh and dismantle the welfare state, live on television.