There exists a comedians' in-joke, only very slightly up its own jacksie, in which one asks: "What's the secret of good com..." only to have the second interrupt with the shout: "Timing!" But that is, indeed, the very singular secret of comedy, timing, and W1A, in its second outing, gets it just-so, in the same way that there is only one just-so way in which to shoot cuffs, tap dance slowly, play Chopin or excise a pineocytoma.

Writer and director John Morton has, admittedly, the best of sublime comedy talent to work with. Hugh Bonneville, Nina Sosanya, Jessica Hynes, Jason Watkins. But he has, in this crammed hour, not only to re-thumbnail the personalities with a wizard's thumb but get the timing beyond reproach. To this end, the entire cast are apparently "invited" to spend up to seven hours rehearsing 10 seconds of rapid-fire dialogue. I'm sure the above four could improvise delightfully - been lucky enough to meet two of them, one over drinks after a funeral, another over an extremely fun lunch, and what different people they are, thus what fine actors - but the Morton gene calls for just-so, and the BBC, bravely risking much to rip the ferret out of itself in this wince-out-loud comedy, acceded, in what may well become its finest confection since Fawlty Towers.

Thus, for instance, the five just-so bollards. In more minor hands, the sequence in which the black Range Rover of HRH, an (unseen) Charles, is stymied at the entrance to New Broadcasting House, inside which the welcoming committee have become hogtied by their own insane security protocols, could have been simple farce. The anti-terrorist bollards would just have jumped up and down or spiked Charlie's RR in the sump. Instead, Dave (Andrew Brooke), head of Beeb security, aided only by a ridiculous smartphone and the meaningless catchphrase "we are status-active", manages with a stoic glower to "relent" bollards 2 and 4. And then, in quiet desperation, Nos 1, 3 and 5. There is a full nine-second pause. All bollards down. Then bollard 3 reappears, like a giant erection (as if there's any other kind).

There is glorious timing here, yes, but there's also humanity. Was I alone in quietly cheering whip-smart Lucy (Sosanya) in being the first to make it to the royal meet-and-greet, having left the three witches trapped in their own personalities and also a non-revolving revolving door? Or in feeling, admittedly slightly, a twitch sorry for Will, the good-looking, charming intern with the kind of shoe-size IQ even a mother would struggle to love? If you didn't see it, I just feel for you. Do so. David Tennant's perky voiceovers, dry as sandblasted Ryvita, are worth the licence fee alone.

Radio Times review

An hour-long special of the comedy where the BBC looks at itself in a fairground mirror. As usual, writer/director John Morton happily tramples on touchy subjects. Not just in the subplot about Jeremy C****son (his full name cannot now be broadcast, due to events) saying "tosser" on Top Gear with controversial frequency, but in the main disaster-in-waiting: a visit to New Broadcasting House by Prince Charles. Head of security Dave (Andrew Brooke) briefs Ian Fletcher (Hugh Bonneville) on the protocol for the Royal Range Rover's arrival: "I will at that point assume control of the rising bollards personally." Dave also plans to lock all internal doors in case of emergency...

When it eventually gets going (I know the myriad characters who say the same thing over and over are meant to be annoying, but still) it's a fine farce, albeit one in which director-general Tony Hall's much-anticipated cameo is still as yet unviable.

Now on a second series, John Morton's comedy is less a satire of the BBC in particular and more a satire of big organisations in general. Endless meetings, managers with no discernible purpose and interns who outstay their welcome are all present and correct, but this week's hour-long special also benefits from the comic talents of PhoneShop's Andrew Brooke.

John Morton's affectionate satire of the inner workings of the BBC makes a welcome return. It has been accused of failing to go for the jugular, but that was never the intention. It's not about attacking the BBC, just as Twenty Twelve wasn't about attacking the Olympics.

According to Hugh Bonneville, it could just easily be about the NHS or Whitehall. "It's about satirising management structure and management speak," he says. W1A has two obvious and outstanding qualities. The first are the characters, all of whom are hideously recognisable and superbly performed.

Jessica Hynes steals the show as the grotesque PR supremo Siobhan Sharpe, but nobody in the ensemble cast puts a foot wrong. My personal favourite is Neil Reid's Controller of News & Current Affairs played by David Westhead, but there's a gem of a performance in tonight's hour-long episode from Andrew Brooke as the BBC's incompetent head of security.

It's other great quality is the dialogue, which sounds so natural that it feels improvised. Not so. "Every um and er - every odd word you hear - is there intentionally," says Bonneville. Because of this, the cast have to rehearse like an orchestra to get the rhythm right. "You spend your entire day running lines, running lines, running lines," says Bonneville.

When a new sitcom gets a big tick from comedy aristocrats like Ricky Gervais and Stephen Merchant, you approach it with enormous expectations. And while PhoneShop includes some sharp lines and clever ideas, it's also irritating, which blurs out much of the good stuff. Double act Ashley (Andrew Brooke) and Jerwayne (Javone Prince) both talk like Ali G, but have nothing especially funny to say. Their schtick is to bully the freshly recruited, drippy salesman, Christopher (Tom Bennett), who they call Newman. This quickly gets boring but their dynamic never evolves beyond lions-picking-on-an-antelope. If you can be bothered it might be worth one more look but at best this series opener feels like an ill-cast early draft.

There was a lot of love on Channel 4's website following the pilot for PhoneShop, which is just as well, because it had been greenlit for a full series before it even went to air.

This well observed, sharply written comedy reunites Ashley and Jerwayne (Andrew Brooke and Javone Prince) to spout more incomprensible rapid-fire banter.

Having survived the infamous one-day trial, Newman (Tom Bennett) is now an official employee and Pay As You Go girl Janine (Emma Fryer) longs to be taken seriously enough to be assistant manager.

Thankfully, there's no mention of manager Lance's sex addiction tonight. Instead, he's fixated on legendary former employee Gary Patel, who is currently at Her Majesty's Pleasure. Meanwhile, a visit from rivals in Croydon forces them all to close ranks to battle the outsiders.

It's very funny, but viewers outside London whose ears aren't assaulted by urban youth-speak every day might want need reassurance that yes, we are still in Britain.

The second sitcom try-out in C4's Comedy Showcase season, and this one packs some more heavyweight comedy credentials. It boasts Ricky Gervais as script editor - a solid gold seal of approval. Disappointingly, there's no sign of former EastEnders Dean Gaffney or Shaun Williamson who manned the phone shop in Extras. This one is staffed by Ashley and Jerwayne (Andrew Brooke and Javone Prince).

Emma Fryer's in it too, still wearing that dazed, sleepwalker expression that she used in BBC2's Home Time.

Tom Bennett is new boy Chris, trying to make his first sale in the cut-throat world of 24-month contracts and impress his sex addict boss (played by Martin Trenaman).

Written, directed and produced by Phil Bowker (who also produced Sharon Horgan's Pulling) I hope this one gets the go-ahead as a series too.

The cast gel together as if they've worked together for years and even manage to turn BNP leader Nick Griffin into joke fodder.