Channel 4 reminds me of the Scandinavian fashion store Cos, by which I mean it used to be great and now really isn't

Why Am I Still Single and Eye Spy is my evidence for this.

Two stars of the reality TV show Why am I Still Single?
Trading places: singletons Naomi and Lex. Photograph: Channel 4.

Why Am I Still Single?
Eye Spy
Channel 4

Lately, Channel 4 reminds me of the Scandinavian fashion store Cos, by which I mean it used to be great and now really isn’t. Nothing seems to fit; everything feels just a little bit cheap and tatty. I visit only rarely, if at all. The other evening, I watched two of the channel’s latest shows – Why Am I Still Single? (26 June, 10.35pm) and Eye Spy (27 June, 10pm) – back to back. Afterwards, I felt precisely as I did the last time I was in a Cos changing room: a slight headache, low feelings, a crazed desire for alcohol and cake.

Why Am I Still Single? is a more prurient and less witty version of that old Channel 4 hit Wife Swap. Two singletons who’ve never met switch lives. They live in each other’s homes, meet each other’s friends and exlovers and visit each other’s workplaces. At the end of this, they hook up and unveil their “findings” face to face, a bit of tough talking that is supposed to help them date more successfully in future.

I’m guessing the film I watched is a pilot (it was screened as part of Channel 4’s “mating season”) and all I can say to those who might green-light a series is: please don’t. Thanks to reality television, we’ve gone as far as we possibly can with this kind of documentary. In front of the cameras, people no longer react; they perform, like over-sexualised monkeys.

Lex worked in advertising and Naomi was the world’s least-funny stand-up comedian. I loathed them both on sight. He was a manchild, reduced to hysterics by the sight of her vibrator (strange how quickly he found it). She was a gurning drivel-head who imagined she could tell how well endowed (or not) he was simply by examining his boxer shorts. You might think that from this low base things could only improve – but no. Down the hill we rolled, my queasiness rising with every tedious bump along the way.

Naomi was obsessed with masturbation. Did Lex indulge at work, she asked his colleague? Lex, meanwhile, was telling Naomi’s girlfriends about her vibrator over a pizza. He was so struck by this piece of pink plastic that, later on, when he confronted Naomi’s on-off boyfriend over a pool table, I half expected him to whip it out and use it to beat the recalcitrant fellow over the head.

Anyway, to cut to the chase, the upshot of this mutual “investigation” was that Naomi would do well to quit the smutty talk and Lex should lower his expectations a little (and, perhaps, learn not to rifle through the knicker drawers of potential girlfriends). Well, woo-hoo.

Eye Spy is Candid Camera for the tabloid age. It’s presented by Stephen Fry, who believes that most people behave less badly than the tabloids suggest. As it happens, I agree with him. But is the best way of trying to prove this to put them in difficult (and, to be honest, highly unlikely) moral situations and then secretly film them? I can’t think that it is. What do these stunts prove? Nothing.

In the first episode, an actor pretended to be a racist waiter abusing a couple in a restaurant (also actors, one of them was white and the other black). Naturally, the other customers at first took their lead from the couple, who, for the trick to work, had to remain mostly quiet and compliant throughout the waiter’s loopy and increasingly over-the-top attacks on them (though ultimately many of their fellow diners did weigh in on their behalf). Not only did the film fail to acknowledge this, it was impossible to judge how it had been edited and how audible the actors’ voices were.

Another test involved a boy in a wheelchair with a fake plaster cast on his leg. I wasn’t surprised that people walked straight past him – as one of them pointed out, the cast was so obviously bogus – and I felt sorry for the two poor saps who did offer to carry him up several flights of steps, only for the gleeful camera crew to appear, release forms presumably in hand.

I strongly dislike the feeling of judgement and entrapment that hangs over this series, a sententious and slightly creepy mood that persists even when people behave well. Given how much real injustice there is in the world, I’d have thought that Channel 4’s considerable resources could be put to far better use than on such a trashy, pernicious experiment as this.