Ian McKellen and Derek Jacobi have a ball as a bitching couple living in a cobwebbed, sepulchral flat, lusting after hunky new neighbour Iwan Rheon, confiding in best friend Frances De La Tour and hamming it up wherever possible. It's a very traditional studio sitcom setup, made watchable by its stars and enjoyable by a waspish script. Also, in its combination of old age and homosexuality, it could be argued to have broken a little ground. Not that creators Mark Ravenhill and Gary Janetti much care about that: this show is all about low blows and easy laughs - at which it excels.

Derek Jacobi and Ian McKellen are Stuart and Freddie, a bitchy, bitter couple holed up in their dingy London flat. In this first episode, the pair become fixated with a handsome young neighbour, as does their brazen friend Violet (Frances de la Tour). With all the very loud talking and theatrical self-pity, this could have been a superbly camp sitcom, but the characters aren't nearly outrageous or monstrous enough. That is clear from their pedestrian put-downs: "At least I'm not from Leytonstone," being Freddie's stock comeback.

If you want to watch a couple of knights slinging bitchy dialogue at each other, Monday nights now offer a surprising alternative to Game Of Thrones.

Sir Ian McKellen and Sir Derek Jacobi star in this fabulous new sitcom which is, believe it or not, even better than the trailers promised.

Together for nearly half a century, Freddie and Stuart are like an old married couple, bound together by their mutual dislike. But they love each other really, of course. I think.

Every line is a belter, which is absolutely what you'd expect when you find out its creators are American Gary Janetti (writer and producer of Will & Grace[/o] and one of the [i]Family Guy writing team) and playwright Mark Ravenhill, who once said he'd be happy never to write another gay character again. I'm glad he changed his mind.

While gay relationships have long been just another part of the furniture on TV, there's never been one like Freddie and Stuart's and certainly not one so perfectly acted.

Frances de la Tour, who plays their friend - would-be maneater Violet - is something of a revelation too. It's taken 35 years but she's finally got another TV role as memorable as her Miss Jones from Rising Damp.

Young Iwan Rheon (Misfits, Games Of Thrones) is set to brighten up all their lives when he moves in to the flat upstairs.

I feel ever so sorry for ITV's second new sitcom of the night for having to follow a tough act like Vicious... The Job Lot, set in a job centre don'tcha know, can't help but pale in comparison to the savage brilliance of Ian McKellen and Co.

And that's a shame because while it's not going to win any prizes for originality (League Of Gentlemen's job-seeker sketches set the bar pretty high on that score), it's a perfectly respectable addition to the clutch of office-based sitcoms.

Plus it's from Big Talk, the company that gave us Spaced, Black Books, Rev, Friday Night Dinner and Him & Her, so it knows about sitcoms.

Sarah Hadland, Russell Tovey, Martin Marquez and Emma Rigby are among the staff turning the unemployed into the funemployed, with varying degrees of success.

But the biggest surprise of the night must be actress Sophie McShera being cast as a job-seeker who's turned being work-shy into a something of a full-time career. It's Downton's Daisy Mason as you've never seen her before.

Ian McKellen: We know we've got our lives behind us now

"Do I think about death? Yes, every day. People of our age, when we get together, talk about decrepitude all the time"

The humour may not exactly be top drawer, but the cast list of ITV's latest stab at primetime comedy can't be argued with. Sir Ian McKellen - Gandalf! Magneto! - and Sir Derek Jacobi - Claudius! The Master! - together... surely it can't be that bad?!

The Sirs play geriatric gay couple Freddie and Stuart, who in this opening episode decide to throw a camp and catty wake for their recently deceased friend. Gurning Misfits actor Iwan Rheon also appears as sprightly leather jacket fan Ash, who's just moved in upstairs, while another acting heavyweight Frances de la Tour plays the couple's ravenous friend Violet. The jokes are groan-worthy, clichéd and occasionally offensive, so we don't expect everyone to come away from Vicious having loved it, but legends like McKellen and Jacobi cosying up together on the same sofa just has to be seen...

A studio-bound, single-set, multi-camera sitcom, Vicious is a gratifyingly old-school farce in which thespian deities Sir Ian McKellen and Sir Derek Jacobi have a char-grilled whale of a time as an incessantly bickering homosexual couple. Sealed within their sepulchral Covent Garden abode - they shriek like vampires when the curtains are accidentally opened - pompous actor Freddie (McKellen) and retired bar manager Stuart (Jacobi) tussle waspishly over decades of perceived slights, while never missing an opportunity to mock each other's supposed decrepitude.

Now, these are hardly original comic creations - the vituperative, hammy old queen has long been a staple of popular culture - and there is nothing especially notable about the premise. But that simply doesn't matter when the execution is as strong as this.

Resembling a startled, wounded guinea pig, Jacobi squeals and frets amidst a knowing flurry of camp mannerisms, while McKellen booms fresh insults in that oak-lined voice of his. He also pulls some of the funniest "Why, I've never been so insulted in my life!" expressions this side of imperial phase Frankie Howerd. It's an impeccable dual assault of seasoned comic timing.

Enjoyment is magnified by the addition of Frances de la Tour as their dotty, man-hungry pal. Famously, she starred in Rising Damp, one of ITV's few great sitcoms, and it's tempting to view her presence here as a deliberate nod to the past. Not that her involvement is merely symbolic - she's a peerless comic actress - but you could argue that she's essentially playing lonely Miss Jones 30 years on. Even the dingy brown set recalls her most celebrated role.

Broad and boisterous in the best possible sense (ie it's nothing like that avalanche of horror, Mrs Brown's Boys), Vicious is jam-packed with gags, hitting the ground running with an impressive opening episode which establishes set-up, character and backstory with consummate ease.

A co-write between acclaimed playwright Mark Ravenhill and Gary Janetti, a former executive producer on Family Guy and Will & Grace, it revels in its camp bluster with such benign relish, I doubt it'll get into too much trouble for reinforcing stereotypes. It's obvious that Freddie and Stuart are blissfully happy in their enmity, and it's that undercurrent of warmth - the spoonful of sugar beneath the barrel-load of bile - that make these characters so engaging.

I'm no soothsayer - I've never said "sooth" in my life - but I predict that Vicious will be huge. A hit sitcom! On ITV! Nurse, the smelling salts...

Can you believe they managed to get Sir Ian McKellen and Sir Derek Jacobi on a TV show together... and then forced them to make awkward '70s sitcom-esque gags? Nah, we kid. Vicious seems like good fun, and we'll be tuning in just to see how wide Iwan Rheon can get his mouth to open. Seriously, in the trailer his jaw is flopped down like a Sesame Street puppet.

Sir Ian McKellen: Don't call me old

Ian McKellen says the title of a new ITV sitcom was changed from Vicious Old Queens to Vicious when he joined the cast as he did not want to be called 'old'.

New Channel 4 comedy The Mimic appears to have been built around the ability of its lead actor, Terry Mynott, to do impressions and there are moments when you wonder whether he provides a solid enough foundation. His Terry Wogan was very wobbly and his David Attenborough was a weird hybrid of Alan Bennett and Ian McKellen. Other impressions are so left-field they have to be visually signposted or cued up by a line of dialogue to make sure we get them.

But there was a promising little sequence as Martin (Mynott's character) sat slumped in front of his television and Morgan Freeman and James Earl Jones fought it out over who was best at adding gravitas to a natural-history programme. It's a comedy of underachievement essentially, complete with marimba noodling on the soundtrack to signal the underlying pathos, but it has some lovely downbeat moments and funny silences where some comedies might strive (unsuccessfully) for a big guffaw. Look out for Jo Hartley as Martin's friend Jean too. She's very good, so quietly you might miss it.