After four episodes, BBC’s “steamy” drama of four modern mistresses is certainly hotting up. About time, you might think. It’s taken four weeks to plod through “shagging by numbers” and deliver the girls into the set of circumstances that, had I written my predictions on a postcard and sent it to myself, would have played out exactly as expected. The one whose husband is infertile has fallen pregnant to her office lover (Siobhan), who started off as a mere diversion but now might offer more than she realised she wanted. The one who thought she’d “try a lesbian” because she’d already tried pretty much everything else (Jessica), has gone and fallen in love with her tester. And the one who’s lover died and who started “comforting” his son (Katie), has found herself in the centre of a maelstrom that could wreck her career and pretty much her whole life.

So thank God for the comic relief that is Trudi. The only story that wasn’t entirely run-of-the-mill from the start (although if I’d thought hard enough…) has provided some of the funniest moments of this mostly drab drama, even if she is faintly unbelievable.

“Something doesn’t feel right,” said Jessica to Katie last night. “I’ve never felt like this before.” Was it that her emotions and her bodily cravings (or something) were operating together for the first time, Katie mused? Yes? Then you’re in love. With such depth of understanding it’s a wonder they both don’t drown. But I suppose, in the distant world of mixed-up urges and multiple partners Jessica inhabits, and having tried to mix and match all her lovers in an attempt to recapture that frisson she felt with the soon-to-be-married Alex, it’s just possible she’d never been in love before.

There’s clearly danger ahead for Alex’s marriage.

In the end, and I suppose the best we can say is “for the time being,” Hari was amazed, grateful and deliriously happy that Siobhan is pregnant with “their” baby. Maybe if you want something badly enough, no matter how small the chance when it happens you just accept it. Once Hari is alone with his thoughts and has time to calm down and look at things objectively, he might realise that that vanishingly small chance doesn’t explain the baby, and start to look for alternative explanations. He won’t have long to wait. The baby isn’t going to look anything like him. Siobhan better come clean, and soon.

Katie’s headlong rush into a mad affair with young Sam is not only ill-advised it’s more than a little far-fetched. Either way, they’re not doing too much to cover it up. I’m surprised there’s been (so far at least) no reaction from his mother. His reaction to Katie’s long-delayed revelation that it was indeed she who was engaging his father in afternoon delight was well played, I thought, but I expect the fallout to be dark and heavy.

And so to Trudi. Dear, sweet, innocent Trudi, with her seaweed wrap and her red basque, her wide-eyed disbelief that anyone could be interested in her and, at the same time, that her husband could spend a couple of years in New York and remain faithful. Not to mention her surprise at learning that the “other woman” was after…money! Imagine that.

Mistresses is another one of those dramas, like Lark Rise to Candleford, that defies my attempts to dislike it. Too easy to pick holes in, but it’s easy on the eye. It’s populated by beautiful people doing beautiful things to each other, so on that level at least it’s an interesting watch, but if you’re looking for deep and meaningful, I’d look elsewhere.

And lastly, out of interest, since the subject of infertility and gay relationships peppers the hour, why don’t we get one of those annoying public information bulletins at the end of each episode? “If you’ve been affected by any of the issues…etc”. Come on! We need some nannying!