Anyone who thinks theatre costumes are incidental decorations should go to Sound of the Underground. Anyone who thinks that drag performances are only about frocks should join them. Travis Alabanza’s new show, created with Debbie Hannan, brings queer culture to the Royal Court in a glorious, multiforked parade of talent. It sets out to rescue performers from the jostling commercialism of RuPaul, the villain of the evening, and from being wheeled on to strut predictably at hen parties. It aims to celebrate the individual work – song, movement, the making up of a persona in front of an audience – that used to take place in sticky basements. It discusses difficulties, from verbal abuse to low pay. It teases the Court’s audience and parodies its stage: a bucket is sent around for money; a glossy kitchen-sink scene, styled with a “Cos-style aesthetic”, has actors snapping and pausing portentously while they make tea. So here am I, not only cis but wearing Cos: a natural target in an evening that points out how weird it is to whoop if asked if you are white or straight. Yet being targeted is not what it feels like: the joy and success of the evening is in bringing a sense of enlargement, not only to the stage but to the audience. For once, a piece of work that talks about exclusion does not itself exclude. Sound of the Underground is not an argument: it is a declaration. After a first half of introductions and satire comes cabaret. A burlesque striptease by Lilly SnatchDragon, who treats her breasts like a handy shelf for storage purposes; a powerfully throated reinvention of Cheeky Song from Ms Sharon Le Grand; Chiyo, a brown trans man, moves dextrously from strip dance to describing being attacked in the street. Feats of lip-syncing make this seem the tongue equivalent of drag. Sue Gives a Fuck begins sinuously in a red split-up-the-thigh number. As she becomes a graceful and knowing compere/commere, she settles into a deconstructed Cinderella-cum-Pompadour transformation gown: peach-coloured, puffed sleeves, winking rosebuds, with the front almost entirely cut away, designed by Julian Smith. In front of Rosie Elnile and Max Johns’s yielding design of a fabric palace, the challenging and appealing Midgitte Bardot appears rigged out by Alexandre Simões in shades, bum-hugging skirt, cleavage like a command, and (thanks to Darren Evans) a beehive as tall as her – and my – legs. Several of the garments have (there must be a technical term for this) bottom windows – transparent frames at the back of the frocks which frame cheeks and cracks. Some dresses are gorgeous, some like satirical armour, some uncanny. They are so expressive they are practically animate. It’s enough to make you think that speciesism should include another category: fabricism. Sam Steiner has watched his first play rise steadily to phenomenal success. He wrote Lemons Lemons Lemons Lemons Lemons when he was 21; it was produced at the Warwick Arts Centre in 2015 and later that year on the Edinburgh fringe; it has been staged in Mexico, Turkey, China and Russia. Now, as the playwright turns 30, it canters into the West End, with Josie Rourke directing Aidan Turner of Poldark and Doctor Who’s Jenna Coleman. The premise is ingenious: a new law of Quietude – cleverly nicknamed the Hush Law, to rhyme with sus – decrees that the inhabitants of what seems to be England are allowed to speak only 140 words a day; Twitter has cast its shade. The dilemmas to which this gives rise are intriguing: would people hoard their words? Would a young couple find themselves forced by the limitations into lies, or would they find a way of encoding their feelings? Would the ban, as Turner’s character claims, exacerbate social divisions, “cutting the working class off like a bad piece of meat”? Would it, as Coleman speculates – as a lawyer she is used to playing devil’s advocate – mean less workplace bullying? The questions tick round as they might in a Christmas board game. Sometimes they gain an added echo, as they brush against a present-day dilemma: how do people adapt, protest, confine themselves under sudden arbitrary change – hush or pandemic? Is this word-cutting the last measure of a governing party hellbent on austerity, at least for the governed? Yet a vital sense of disturbance is almost entirely absent. A cut-up chronology means that the necessarily elliptical plot lacks propulsion. Coleman is bright, quick but edgeless. Turner has a strong, relaxed presence, ambling with ease towards a kind of coercion. Yet their exchanges are rarely urgent: they are careful with each other, as if they were moving around avatars rather than their own lives. Fleetness is not helped by Robert Jones’s design, which stacks a dark wall with closely packed objects – a bicycle wheel, a guitar, a shopping bag, a bedhead – presumably to remind us of jettisoned words: it’s impressive but distracting, though Aideen Malone’s lighting cleverly shoots up and down, fading in and out to mark the passing of time. Spare, serpentine duologues – Duncan Macmillan’s Lungs and particularly Nick Payne’s Constellations – have provided high points of the last 10 years. To join them, Lemons Lemons Lemons Lemons Lemons needs a quintuple dash of acidity. Star ratings (out of five) Sound of the Underground ★★★★ Lemons Lemons Lemons Lemons Lemons ★★★ Sound of the Underground is at the Jerwood Theatre Downstairs, Royal Court, London, until 25 February Lemons Lemons Lemons Lemons Lemons is at the Harold Pinter theatre, London, until 18 March