Lemons Lemons Lemons Lemons Lemons review: Aidan Turner and Jenna Coleman squeeze out the juice

“Hip hop is as good as dead.” In Sam Steiner’s spirited play, it’s one of the many casualties of the “hush law”, which restricts citizens to 140 words a day. Also not long for this world are presentations, wedding speeches and epic poetry. And there are greater problems still. It will be hard to challenge those in power. Nepotism will thrive (job interviews take up too many words). And what about children – will they just “have to be very concise from a very young age?”

These are the issues debated by a young couple in Steiner’s dystopian romcom, first staged at the Edinburgh Fringe in 2015. Jenna Coleman is Bernadette, a passionate lawyer from a working-class background. She sleep-talks, which means she’ll have to gag herself at night. Aidan Turner is Oliver, a preening musician who is engaged in a protest movement against the law – which happens to be led by his ex-girlfriend. The action jumps around, splicing scenes from their relationship, beginning with their first meeting at a cat funeral (whimsy alert) to life after the hush law comes in, when they announce their remaining word count to each other as a form of greeting.

There’s a lot of fun to be had with this concept, which feels slightly dated by the clear influence of Twitter (a platform that’s long since jumped the shark) but fluid enough to keep us thinking. Bernadette and Oliver begin with puppyish determination to hack the law, through joining words up (“I love you” becomes “loveoo”), Morse code, or trying to impart thoughts through eye contact. Coleman and Turner are brilliant at portraying how quickly exasperation sets in, conversations becoming like rushed-off telegrams, or spoken as though they’re laboriously trying to order dinner in a foreign restaurant. Words become something to preserve for one another, withhold in anger, or accidentally waste in the search for expression. The law doesn’t just hamper communication, but cuts short the innately human quality of being curious.

The actors make for a charming duo, with Coleman particularly strong as quick-thinking Bernadette, who doesn’t always need words to understand what is going on. And Steiner’s writing is genuinely exciting – fresh, funny, thoughtful. But it feels overstretched on a West End stage, pulled to its limits to justify a longer running time, giving it a whiff of celeb vanity project. Nor does the production, directed by Josie Rourke, match the inventiveness of the script. With the towering backdrop of Robert Jones’s set, looking like an oversized cupboard under the stairs, and the couple dressed dowdily, it feels stuffy and domestic, rather than intimate or risky.

The main attraction is Steiner’s writing – Lemons was written when he was just 21. There’s obviously something nice about the fact it’s been plucked from its fringey origins for a starry West End show. But if theatre believes in new writing talent, shouldn’t Steiner have been commissioned to write a new play, one that suited a bigger stage? I was left wondering why an early work, one that clearly worked better in a studio space, was plonked into this massive auditorium. The programme tells us that Steiner is working on a handful of starry film projects, so why hasn’t theatre done more to develop a body of work from an exciting talent? If it wants to bring new voices through, it surely has to commit to them less superficially. Lemons is about the power of words and the perils of restricting language; it strikes me as a strange irony.

Harold Pinter Theatre, 18 March; Manchester Opera House from 21 to 25 March; Theatre Royal, Brighton from 28 March to 1 April