Last Night's TV - Sirens, Channel 4; Dirty, Sexy Things, E4; Guilty Pleasures, BBC4

Let me start with an apology for repeating myself, because I'm pretty sure I've already shared with you my very personal reason for not reviewing a new comedy series after only one episode; in fact, I would have shared it with my therapist, if I had one.

If you recall the sorry tale, feel free to skip forward, but if not, here goes. Way back in the mid-1990s, as a TV critic for another national newspaper, I watched the first episode of a new Channel 4 sitcom about three Irish priests who shared a house. Well, I couldn't make head nor tail of it, wrote that it was complete bilge, and for years afterwards the makers of Father Ted joyfully included my scathing review alongside the lashings of praise from everyone else.

So, I've been careful ever since about making an early assessment of a new comedy, and more often than not I've seen the wisdom of that circumspection, because they usually either get better, or get worse. All of which brings me to Sirens, also on Channel 4, and also with three men doing the same job at its core, although in this case the men are paramedics, not priests. As it happens, I liked last week's first episode, and better still, last night's second episode was, well, better still.

Sirens is a comedy-drama that gets its laughs out of character rather than situation, which is where so much comedy goes wrong, and squeezes drama from banality rather than improbability, which indeed is where lots of drama goes wrong.

It is mainly about relationships, and rather like The Three Musketeers, it contains pathos, bathos and Aramis. Actually, it wasn't Aramis but some other scent on another man's underpants that Stuart (Rhys Thomas) found under his new girlfriend's bed. This is the girlfriend with whom he'd been unable to consummate his lust because of issues about his estranged father, at least according to his mate Maxine (Amy Beth Hayes), a policewoman whose first foray into internet dating misfired when she noticed that her date had no tax disc on his car. Really, Sirens is an edgier, funnier, sexier version of Casualty.

It was conceived and written by Brian Fillis, who has struck on something by creating a paramedic, Stuart, who doesn't particularly like humanity. There's a long and illustrious history of misanthropes in TV comedy, and lots of possibilities in a misanthrope whose job, at which he happens to be very good, is to help people. As he says, "I may be a miserable sod, but I can generally get to your doorstep in under eight minutes." Also on board are Ashley (Richard Madden) and Rachid (Kayvan Novak), the latter an amiable dimbo who hasn't yet mastered the job's jargon. "Shall I do the eye thing with the shiny light?" he says.

Stuart drives the ambulance, but it is also driven by testosterone, with emergency calls becoming a race to get to a crisis ahead of the fire engine. I suspect Fillis has hit on something there, too. I'm full of admiration for them, and I hope I'll never need them, but in real life, as in Sirens, there's undoubtedly sometimes a boys-with-toys dimension to firemen and ambulance crews.

Perou is a boy with a toy, too, in his case a whopping big camera. He is a glamour photographer – "Debbie Harry on Tuesday, Bob Hoskins on Wednesday" – who in Dirty, Sexy Things auditioned a bunch of models and chose eight of them, repeatedly declaring his intention to push them as models and himself as a photographer, although to what purpose was never really made clear. Maybe there was no purpose except to offer us some insight into the world of modelling, but Dirty, Sexy Things didn't do that, either. More than anything, it seemed like a vehicle to show some attractive young people half, or rather seven-eighths, naked, and for Perou to show that his brain ticks as quickly as his shutter shuts. On that score, frankly, the jury is still out.

Never mind. I liked Jay, the Londoner with hang-ups about his body (neuroses that could impede his success as a model, observed Perou, percipiently), and Ariella, who reckoned that in the world of glamour modelling "you don't have to go topless to go the top". It's a neat slogan. She could have it printed on a T-shirt, then watch as the other girls take their T-shirts off and get all the best jobs. I even saw a flash of nipple in a watch commercial the other day.

Expensive watches are to us what pattern-welded swords were to our medieval forebears, status symbols and sometimes even assertions of a chap's virility. In Guilty Pleasures, the historian Dr Michael Scott looked at how attitudes to luxury have changed through the centuries, and found in the 14th century the real beginnings of the "forces of consumption that now define our lives ... the cusp of the modern world".

Ostentation, he found, goes in cycles. The monk Cuthbert, in the seventh century, was the pin-up boy for the notion that showy wealth was sinful, but by the 1300s it was all the rage, hence the 1363 Act of Apparel that tried to restrict smart clothing to those of appropriate social rank, rather than simply for anyone who could afford it. Unfortunately, it didn't work, which will come as bad news to the man I overheard on a train recently, complaining about "the oiks in morning-suits" at Royal Ascot.