Monday saw the return of possibly the weirdest TV series in living memory. Imagine a parallel universe in which Are You Being Served? had starred Laurence Olivier, John Gielgud and Janet Suzman, and you might get some idea of what ITV’s Vicious is like. Alternatively, I suppose, you could just watch the thing and realise that no, you’re not drunk — you really are seeing Derek Jacobi, Ian McKellen and Frances de la Tour acting their socks off in a sitcom that would have been considered rather creaky in 1975.

Jacobi and McKellen play Stuart and Freddie: a pair of gay actors who’ve been living together for decades despite the fact that their main mode of communication is to trade personal insults while the studio audience laughs dutifully. De la Tour is their friend Vi, a sex-starved older woman of the kind not often seen since Mrs Slocombe and Dick Emery were in their pomp.

And that’s just the set-up. With commendable attention to dodgy-sitcom detail, Vicious also serves up plots that manage to be utterly predictable and completely implausible at the same time. On Monday, for example, Vi’s sister Lillian came to visit her for the first time in years. The trouble was that Vi had told Lillian that she was married with servants, and would now be rumbled. So what on earth could she do? Cue, needless to say, Stuart pretending to be her husband, with Freddie as the butler.

Yet, perhaps the weirdest thing of all about Vicious is that it’s not terrible — or at least, not just terrible. Each episode tends to contain a couple of moments so unexpectedly sharp that they seem to have come from another show altogether. At times too, there’s something almost touching about the sheer level of shamelessness involved — a shamelessness fully shared by that inexplicably distinguished cast. If you’re not careful, you might even find yourself feeling slightly nostalgic for a more innocent era when sitcoms weren’t supposed to bear much resemblance to real life, only to other sitcoms. Until, that is, the next clunking line or weary set-piece comes along to break the spell.

If, on the other hand, you’d just prefer a good contemporary sitcom, then simply hang around for half an hour and turn on BBC2 for Episodes. Unlike Vicious, this is not only crammed with genuinely funny lines, but it also puts them into the mouths of characters who might actually be likely to speak them.

Stephen Mangan and Tamsin Greig are Sean and Bev Lincoln, a married couple writing for American television, and therefore having their work messed up by various Hollywood executives. (Episodes is written by two old US TV hands, including David Crane who co-created Friends.) The satire, though, is nicely even-handed, with the Brits as guilty of prissiness as the Americans are of shallowness — and in both cases without ever seeming despicable, merely somewhere between ambitious and scared.

Add in a uniformly strong ensemble cast and Episodes should in theory be an impossible show for any one person to steal. In practice, Matt LeBlanc manages it effortlessly, playing a particularly unsparing version of himself as an amoral egotist struggling to hang on to his alpha-male status as his post-Friends career slides ever downwards. On Monday, for instance, he decided that if he got back with his ex-wife, he could renew his relationship with his sons — and, better still, save a lot of money on alimony and child support. And all this, while remaining extremely charming.

Now, the fact that TV critics generally pass judgment on drama series by reviewing the opening episode is understandable enough — but also a bit like reviewing a book from the first chapter alone. And with thrillers, of course, the real test is how they end. Over the past six weeks, The Game (BBC2, Thursday) has left many a loose end dangling as the entire staff of MI5 in the early 1970s — six people, apparently — tried to work out how the Soviets intended to destroy Britain by means of the mysterious Operation Glass. But would they be able to sort everything out in the last hour? Or would we get one of those infuriating cliff-hanger finales that so obviously translate as a desperate plea for another series.

Well, the good news is that The Game did honour its commitment to the viewers. Operation Glass was both revealed and foiled. It also turned out to be suitably dastardly and byzantine, while still comprehensible. The loose ends were all tidied away and the baddies got their comeuppances.

The series as a whole can’t be called dazzlingly original — although, in its defence, it’s not easy to imagine a Cold-War thriller without moles, guttural accents and an all-pervading sense of mistrust. Nonetheless, The Game shuffled the familiar elements with impressive and ultimately satisfying aplomb.