"A&E". Burton Taylor Studio

From its strobe-light-manic opening to its primal fuck-scream of an ending, A&E is a dizzying cascade of wit, pain and razor-blade social satire. Considering the main thrust of the plot is that nothing happens in it - it's literally just people waiting in A&E - the personal stories it unveils pack more revelations than St John the Divine. It's a comedy so black it should have a 90% cocoa warning on the door. It makes fun of middle-class do-gooders, drug addicts, the NHS, the Police, the education system, the audience, and even itself. But it does all that somehow with both bitter contempt and forgiving compassion in equal measure.

And it's been written by a student, Orla Wyatt, who has never penned a play before. How that alchemy happens is beyond me. I'm just privileged to see the result, and to celebrate an unimpeachable hit.

The premise is so simple: we are in the A&E department of Woolwich Hospital in South London. No, really, we all are: captions on the back wall light up to tell us that there are loads of other people waiting beyond the few 'important ones' who feature in the play, and those other patients are watching on nosily. The select few on the stage are a posh woman with a slight cut and a Gail's sandwich, a meth addict called Evie who can't stop scratching, a prisoner who's been injured at the local jail, and someone else who never speaks but does look very, very ill. There's also a bored but hard-working receptionist and two police officers escorting Adam the prisoner.

Sandwich lady (a cut-glass Trixie Smith) and Receptionist (an eye-rolling Ice Dob) double up as the coppers, and their transitions take place in five-second snatches of disco music. The timing is perfect, even down to one of the police officers failing to get her hat on the right way round at one point, a tiny detail that shows how much Wyatt (who also directs) understands about milking and developing visual gags.

Most of Sandwich Lady's dialogue is in the form of one-way phone conversations, and again they are brilliantly observed. Her desperation to get her husband to make the kids' dinner, or to impress her friend with the fact that she was injured while volunteering at a soup kitchen, is damning. And yet, with Smith's fragile performance and Wyatt's script, you can't help pitying her too.

And this three-dimensional layering of satire and sympathy, laden with irony, characterises all the roles. Dob's receptionist is a jobsworth, but she defends the procedures that are there to be fair to all. Ollie Milligan's Adam is serving time for GBH against his girlfriend, but we go away with a greater understanding of how he got to where he is.

It seems churlish to pick out a special performance in such a fabulously team effort, but we're going to have to. Clear the way, because Maisie Lambert is back in town. After a year away from the Oxford stage (Finals apparently), Lambert has returned with what is undeniably her finest performance yet. As Evie the meth-head she is a twitching, scabrous, South London troublemaker: funny, rebellious, and shot through with personal tragedy. I was reminded of her role as a sex-worker in Coco Cottam's phenomenal Bedbugs. But Evie is an even greater creation: a Dickensian grotesque with a heart of gold.

Even amid the comedy, A&E has room for a serious intent, albeit not thrust in your face. The fact that the only two named characters are called Adam and Evie is enough to cast an ironic eye on what we've made of our own Garden of Eden: a waiting room; a Purgatory of our own creation. And the only way to reach the front of the queue and get out of there is to die.

Backing up the writing and top performances is a tech team with as much precision and expertise as the actors. Lighting cues, projected text remarks and sound effects are all delivered with the timing of a Beth Mead cross into the box.

A&E isn't a 'big' play. It's perfectly suited to the tiny BT Studio, and its 60 minutes running time is pitch-perfect duration. With the central ideological battle being between Evie and Sandwich Lady, you might argue that Evie gets more than the lion's share of stage time, and a little rebalancing might even things up. But equally, you might not.

So come and see A&E if you want a reminder of what satire really should be: cool yet angry, witty yet shocking, over-the-top yet contained... and fuelled by a simmering, vast, overwhelming passion for humanity.