The Boy in the Dress musical: behind the scenes

When playwright Mark Ravenhill read David Walliams' much-loved 2008 children's book, The Boy in the Dress, there was a line in it that felt like an invitation: when Dennis, the 12-year-old hero, tries on his friend Lisa's sparkly orange dress for the first time, "he felt so happy he wanted to dance... for a moment they were in their own crazy little musical."

Mark Ravenhill: The secret's out at Edinburgh

The 'in-yer-face' poster boy has two productions at this year's Edinburgh Fringe, including a new collaboration with Secret Theatre.

Only when I watched it for a second time did I work out the point of Vicious. Of course: it wasn't a sitcom. It was an elaborate exercise in trolling.

On first viewing I couldn't understand why, in the year 2013, two gay men - Gary Janetti and Mark Ravenhill - would create a comedy about gay men who conform to almost every homophobic stereotype: bitchy, vain, melodramatic, lecherous, rude, sulky. The programme's working title was Vicious Old Queens. It was as if Germaine Greer had created a sitcom called Dykes, about two feminists who hate men, wear dungarees and have no sense of humour.

Then it struck me. Vicious was a wind-up, its aim to enrage bilious homophobes by rubbing their faces in their own prejudices. "There! See!" the bilious homophobes would splutter.

"Homosexuals are every bit as seedy and unpleasant as I thought! God, they make me so angry, I could... Arrrgh! My chest! Call 999! I'm having a heart attack!"

I suppose there is an alternative possibility, namely that Vicious is just a load of hackneyed old rubbish. But I'm sure that can't be it.

Vicious stars Ian McKellen and Derek Jacobi (quite a coup for an ITV sitcom) as a pair of bickering hams. In some ways it's very traditional. It's filmed on a single set, with a delirious studio audience, and the script contains only two types of dialogue: set-up and punchline. Almost all the punchlines are putdowns. A character will say his dog is 20 years old. Another character will say at least it's younger than these biscuits of yours. That sort of thing.

Slightly less traditional are the jokes about rape. Middle-aged woman: "I'm so frightened I'm going to be raped!" Gay friend, scornfully: "For God's sake, Violet, nobody wants to rape you!" Middle-aged woman: "What an awful thing to say!"

Rape offers such a rich vein of comic potential that I am bewildered as to why the world of sitcom has overlooked the subject for so long. But not to worry, because Vicious remedies the situation within its first ten minutes with not one, not two, but three rape gags in succession, culminating in the following chucklesome exchange:

Man: Nobody wants to rape you.
Woman: Don't be so cruel.

Mercifully, they didn't move on to discuss child rape, or I swear my sides would have just burst. Presumably the writers are saving this for a later episode - not wishing to use all their best material first time out.

Vicious stars Ian McKellen, Derek Jacobi and Frances de la Tour, and I can only surmise that all three have close relatives being held hostage by the production company because I cannot think of any other reason why such luminaries of stage and screen should agree to such dross.

The same applies to highly respected playwright Mark Ravenhill and former Will & Grace writer Gary Janetti, who provided the scripts, presumably encouraged by the regular arrival of loved ones' body parts in the post.

Jacobi and McKellen play an elderly gay couple - one is camp, and the other less so. And that is about as far as the characterisation goes. Their relationship is based upon bickering and making acerbic comments, because that's what gay people do. In episode one, the couple are thrown into a complete tizz because a handsome young man has moved into their block of flats.

The show is so busy trying to be outrageous that it fails to exercise any quality control on the jokes it lets through. "I went to Oxford!" protests Jacobi, when his intellectual credentials are questioned. "For lunch!" replies McKellen. With conviction, it has to be said, because he is a fine actor. But who knows what agonies he must have suffered delivering such a limp line?

The most annoying thing about Vicious - as opposed to being just plain unpleasant, lazy or depressing - is that somewhere in its stagey, studio-bound set-up, populated by stereotypes, is a decent sitcom struggling to get out. Let me know if it happens.

What a line-up for a sitcom; three of our most accomplished actors - Ian McKellen, Derek Jacobi and Frances de la Tour - star, and the writers are the super-talented playwright Mark Ravenhill and Gary Janetti, who used to work on Will & Grace, one of the classiest comedies on American television in decades. And what do you get? Well, not quite the laugh fest that it might have been (or may yet become), but an opener that had a reasonable hit rate.

Vicious is another back-to-the-future comedy, a one-room sitcom with two of the queeniest gay men to grace our screens since the dear departed Larry Grayson and John Inman. If Dick Emery's Clarence had made an appearance he wouldn't have looked out of place and, with De la Tour's presence, it could be called Rising Camp (sadly not my line - I nicked it).

Freddie (McKellen) and Stuart (Jacobi) are a bickering, gossipy gay couple who live in crepuscular gloom in their Covent Garden flat. Freddie is a never-has-been actor ("You may have seen me in a scene in Doctor Who") who has long since lost his Wigan accent; Stuart is a one-time barman who is still not out to his mother. He's waiting for the right time - "It's been 48 years!" cries Freddie.

Into the flat upstairs moves the attractive youngster Ash (Iwan Rheon), who attracts appreciative looks both from the men and their faghag friend Violet (De la Tour); most of last night's episode concerned their convoluted attempts to find out if he was gay or straight. Don't people just ask if they're interested to know?

The cast are clearly having fun with the bitchy lines, but Jacobi is overdoing the flounce and Ash is as yet underwritten. Too much of Vicious relies on tired comedy tropes; older people are gagging to have sex with people young enough to be their grandchildren, they don't know anything about youth culture ("Is Zac Efron a person or a place?" Violet asks); or they're deaf, dotty and fall asleep easily. Oh please. As for the double rape "joke" everyone involved should be ashamed of themselves, including director Ed Bye.

On the evidence of last night's first episode Ravenhill and Janetti can't decide if Vicious is lazy retro fun for all the family, or an edgy post-watershed show that's taking us to places never previously negotiated on British TV. Let's hope it's the latter over its seven-week run.

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.

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.

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...