Greg Dixon: Downstairs sexed up

Jim Carter as Mr Carson and Phyllis Logan as Mrs Hughes in Downton Abbey.

There's a saying - I hope I'm not just making this up on the spot - but I believe there's a saying that goes like this: sex sells. You heard it here first. Or perhaps last.

Anyway, there are also some things, perhaps many things, that sex absolutely can't sell. In fact, sex should be kept the hell away from them because combining them with sex is wrong and will just make everyone feel slightly queasy and want to look away.

I'm afraid poor old, soon-to-be-departed-but-possibly-not-lamented Downton Abbey (8.30pm, Thursdays, Prime) is one of these things.

In Thursday's first episode of the last series it was all anyone - even the dithering and increasingly tweedy Lord Grantham - seemed to talk about, sex, sex, sex! Anybody would think it was 1925. And in fact it is.

First, there was the business of Lady Mary being blackmailed by some vile member of the lumpen working classes for having bonked some fellow with a title in some hotel. Not again, I hear you saying. But for some reason this caused Lady Mary to fall off her horse while out on a hunt, and later led to cheque writing by Lord Grantham when he really should have called the police. This was definitely sex gone bad.

Then there was the business of Lady Plain, sorry Edith, wanting to move to London because, well, in the end there's still no possibility of her getting a husband at Downton. This was probably more about frustration than sex, if I'm honest.

However, the most distressing episode of all the sex talk was the bizarre encounters between Mrs Patmore and the ageing ruin, Mr Carson, about whether, once he and the ageing folly Mrs Hughes get married, he expected to cough, cough with his new lady wife. This was done at Mrs Hughes behest. "Perhaps you could keep the lights off," suggested Mrs Patmore.

"That's not very helpful, Mrs Patmore!" spluttered Mrs Hughes.

Yes it was sex played for laughs. But - cheap Carry On Downton laughs aside - I'm quite sure that no one really wanted the image of an ageing ruin engaged in cough, cough with an ageing folly in their heads. Me least of all.

Of course the very idea that in 1925 in a stuffy country house in rural northern England that one woman would ask another woman to go to the first woman's prospective husband and ask whether he expected their marriage to include cough, cough is simply implausible. But it's just one of the wilder anachronisms that have dogged Downton from start to finish. Reality and the abbey have only ever been on nodding terms.

Still the cold hard world continues to chip away at Lord Grantham's country edifice. He spent the entire episode worrying about whether he had too many damn staff downstairs, and his concerns about the wage bill were only made worse by one of his once-rich neighbours being forced to sell up and, gasp, having to flog heirloom snuff boxes and paintings of ancestors at auction as well.

Sex might have dominated this episode, but you don't have to be a genius, or even a Grantham, to see that upstairs may be planning to downsize Downton downstairs.

I suspect before this last series is over the newly married Mr and Mrs Carson will have more to worry about than whether to keep the lights on.