The histrionics are in full flow when Freddie goes for an audition on Downton Abbey, although his only line of dialogue involves potatoes. The notion of Ian McKellen being up for such a small role is in itself funny, and the scene where Freddie sits gauche young Ash (Iwan Rheon) down for his first acting lesson is priceless.

Freddie and Stuart live up to the promise of the title tonight. They're in waspish mood, not just to each other and Ash but also to Violet - Frances de la Tour getting the best lines. "A lot of acting is just good hair," she avers, while seeking solace for a failed affair with Christoph: "He'd fly me to Hungary once a month to do... unspeakable things."

ITV's Vicious - the sitcom even Ian McKellen can't save

When ITV's new sitcom Vicious premiered last week, I quipped on Twitter that the only way it could be any worse was if Miranda Hart suddenly popped up in it. I'd like to take that back. Because, having tuned in for the second episode on Monday this week, I've realised that this comedy can't actually get any worse.

It's amazing how quickly Freddie, Stuart and Violet, the tart trio at the sweetly sour heart of Vicious (ITV), have become as familiar as old friends.

Only two episodes in and it already feels like we've known them for years. Which of course is the case, because what this defiantly old-school sitcom amounts to is a masterclass in stereotypes.

That it scarcely matters is down to the impeccable comic timing of Ian McKellen, Derek Jacobi and Frances de la Tour, who make the absolute most of what, in lesser hands, could be thin pickings.

Last night offered mild farce in a department store involving a suspected affair and a running gag about a might-be dead dog. Every line was expertly squeezed for laughs.

The real joke, of course, is that Vicious isn't really Vicious at all - it's obvious that, not very deep down at all, they love each other to bits.

Stuart and Freddie persevere with the elaborate sniping as the camp-as-cardigans sitcom continues. The only visitors to their be-cushioned, velveteen world are guileless next-door neighbour Ash, a brace of ageing hangers-on, and an immovable dog. Tonight, Freddie suspects Stuart is having an affair, with almost, but not quite, hilarious consequences. It's somehow a bit old hat while still managing to be a complete delight. Derek Jacobi and Ian McKellen clicking their heels in mid-air does the trick.

Hearing Sir Ian McKellen gleefully call Sir Derek Jacobi "a cheating slut" is a joke we're not going to get tired of for ages.

And that's one of the less vicious insults being hurled about in episode two of our favourite new sitcom.

After their hilarious vampire-like horror last week at the curtains being opened, Freddie and Stuart actually venture out into daylight this week.

New neighbour Ash asks them for their advice about women, actor Freddie is excited about the Doctor Who fan club screening that he's about to attend (having been voted 10th favourite villain of all time) and Stuart is suspected of having an affair.

But truthfully, the plot scarcely matters when the dialogue is so delicious, the relationships so sharply drawn and the acting so sublime.

Frances de la Tour ("you remember our friend Violet") continues to drop by unannounced to purr throatily over Ash, but it's their other dotty friend Penelope (Marcia Warren) who delivers one of the lines of the night. Actually, make that the whole year.

Tonight, Freddie and Stuart emerge from their fusty flat to visit - for them - an alarmingly bright clothing store to buy a smart overcoat. Freddie, an actor whose ego is far more swollen than his CV, needs to look his finest for a Doctor Who screening - "I have been voted the tenth most popular villain of all time!" he coos, making the most of this dubious accolade.

What gives this a curious subtext is that Ian McKellen actually did voice a baddie in Doctor Who last Christmas, while Derek Jacobi played number-one villain, the Master, quite thrillingly in 2007 and has attended several conventions himself.

A torrent of tart asides, camp banter and even dog prodding flows in this terrific new comedy. Frances de la Tour is magnificent as Stuart and Freddie's man-eating pal, Violet, whose "rather broad tastes" will extend even to Who fans. Meanwhile, she's panting after their neighbour Ash, takes him shopping too and tries to get him into a pair of Speedos - all of which allows Ash (former Misfits star Iwan Rheon) to appear less gormless than last week.

A new flagship sitcom for ITV, Vicious stars Ian McKellen and Derek Jacobi as the bickering, aging partners Freddie and Stewart. This show surprised me for three reasons; a) it's an ITV sitcom, b) it's filmed in front of a live studio audience and c) I didn't hate it. The cast alone should be the first clue that this is going to be something much better than you would expect from a channel which isn't exactly famous for modern sitcom greats.

Set in the darkened, dingy flat of Freddie and Stewart, the pilot doesn't faff about setting up back stories and characters, and therefore the opening episode isn't a total comedic write-off. Some of the writing isn't exactly subtle but it can be forgiven. Naturally, the performances are fantastic; the cast of well-established actors are entirely believable, despite the live studio setup. It doesn't feel like it panders or patronises, and it moves along at just the right pace.

There are things that I would change, of course. I would move it from the live studio and into single-camera mode, for one. But that's just preference. It definitely runs the risk of feeling dated, and the whole setup will either stand or fall based on the quality and originality of the episode arcs.

I've heard it said that it is a very bold statement to set up a 70s style sitcom starring two gay men, but let's not dwell on that too long. I will just say this: it's a long time coming that members of the LGBT community aren't portrayed in comedy as subjects of mockery and, for me (admittedly, a straight man) the roles appropriately show a couple who happen to be gay, rather than making their sexuality the butt of the joke.

For just when you thought TV couldn't get any more 1973 following from the BBC's The Wright Way, along comes ­Vicious, a comedy with Sir Ian McKellen in a silk dressing-gown standing regally - nay, queenly - on a staircase and squawking camply at Sir Derek Jacobi in a fetching sleeveless pullover who's squawking camply back at him.

The trouble with The Wright Way is that it doesn't seem as if Elton is being nostalgic for how sitcoms used to be, or that he's operating in defiance of shows like The Office and all those pale imitations, churned out of David Brent's hyper­active photocopier. The Wright Way appears to be the funniest and most relevant programme he could make, which isn't very funny or relevant at all.

Vicious, though, is a more self-conscious attempt to evoke the spirit of '73. It's completely stage-bound. We never leave Freddie and Stuart's flat. The doorbell rings often; phone, too. Sometimes Stuart (Jacobi) shrieks: "These aren't calling hours!" Most likely, there have been very few callers in the 40-odd years the pair have lived together, blissfully ignorant of the changing world (acceptance of homosexuality, not all comedy looking like Brian Rix is about to enter, stage left, mightily flustered). A modern sitcom like Modern Family has its gay couple flamboyantly "out" and adopting babies; Stuart hasn't even told his mother about Freddie.

Why's it called Vicious? Well, these guys are very bitchy. "Are you wearing mascara?... Your mother looked well for someone who doesn't have a heartbeat... I'm surprised you can see it through the milky film that coats your cataracts."

At first I quite enjoyed the campery. Frances de la Tour popped in, reminding us of her big 1970s flat-based hit (what was it called again, Rising Camp?). But, in every sense, where can this one possibly go from here?

Radio Times review

Vicious (ITV Player) put Derek Jacobi and Ian McKellen on a standard stage/sitcom lounge set - front door on the left, swing door to the kitchen on the right, stairs in the background - and let them howl and scratch for half an hour as Freddie and Stuart, who had been lovers for more than 50 years and had now settled into their bitter, argumentative dotage on the sofa.

The challenge was to enjoy the proceedings as much as the two stars, as McKellen ripped through scores of searingly bitchy lines, peaking with a cracker about Stuart "pouring your blandness over every surface", while Jacobi freed his right arm to become one of the campest limbs ever seen on TV.

Many viewers really, really didn't enjoy Vicious, throwing all sorts of criticisms that largely bounced off. It was stagey, retro and gaudy, they said, pointing out all the things it was actively trying to be. It entrenched gay stereotypes, they said, looking to a riotous sitcom for assiduous social realism. It used canned laughter, they said, referring to the live studio audience.

The complaint that had merit was that jokes mentioning rape are basically never funny, even if Frances de la Tour as fag-hag Violet fretting about virile young neighbour Ash (Iwan Rheon) was cartoonish and abstract enough to be as near to harmless as they come, as well as being sinfully well timed. (McKellen: "For God's sake Violet, nobody wants to rape you!" De la Tour: "What an awful thing to say.")

The line still should have been taken out, and was evidence that Vicious might not have a heart, which means it'll drag as soon as the one-liners falter. But while it's steaming, Vicious is hot.

Vicious stars Ian McKellen and Derek Jacobi as a pair of gay old queens sharing their lives and a crepuscular flat that looks like a relic from a 1970s sitcom set.

That design may well be a consciously ironic reference but it didn't make the setting any more appealing. There was something dankly theatrical about it. In theory, that befits McKellen's role as an ageing rep actor who, in the show's best line, "once killed a prostitute in Coronation Street".

But there was also something dankly theatrical about the whole concept - the over-pronounced acting, the laboured dialogue, the arch gestures, McKellen's dressing gown - that felt like being trapped in a dramatic workshop on camp with two self-regarding thespians, but not nearly as amusing as that sounds.

Of course, the radical new aspect of the show is that it's a sitcom about gay men on mainstream television. While that's a development worthy of applause, it doesn't, unfortunately, command laughter. Nor did Frances de la Tour, reprising her Rising Damp role 40 years on, but this time more as a female Rigbsy than an older Miss Jones.

She found herself in the unenviable position of having to try to out-camp Jacobi and McKellen, which is rather like having to out-butch Schwarzenegger and Stallone. Everything was at a hysterical pitch, but nothing happened. Instead, the dreadfully static nature of it made you long for the energy and pace of the commercial break.