‘Write what you know’ has never been more apt. When a former Daily Express entertainment editor writes a play in which the showbiz section of his lightly fictionalized newsroom is called “Cunts’ Corner” you know you’re in for a fun and filthy ride. Ruder about interfering proprietors than Drop the Dead Donkey, more racist and sexist than Malcolm Tucker in The Thick of It and just structurally shy of Richard Bean’s more smoothly-crafted Great BritainMark Jagasia’s Clarion is an uproarious debut and a stonkingly good cartoon of the dying and desperate days of ink-fingered journalism.

It has wistful echoes of Waugh’s Scoop or Frayn’s Towards the End of the Morning too, reminding you it wasn’t always like this. Never more than in Clare Higgins’ meticulously-observed Verity – a once-garlanded foreign correspondent now drowning in cheap wine and care-home bills and reduced to grinding out op-ed rants for an unworthy red top. Higgins so slyly pins the gravelly weariness of the veteran hackette that if it’s not meant to be Dame Anne Leslie, I’ll eat the biggest dog in Fleet Street. The four-legged one.

It’s a pity we live in an era of cash-for-libel lawsuits because this could be juicier if it named the individuals or papers it lampoons: the plot turns on whether by publishing every day for a year a front-page story about immigrants, a tabloid could incite an act of racist violence. It waits too long to explode the bomb that makes the narrative darker, and loses vital energy in the second act.

Salvation comes in the constantly ferocious turn of Greg Hicks as the foul-mouthed editor Morris Honeyspoon whose reactionary posturing makes Nigel Farage look like a tentative nervous liberal. Hicks gives the script a gargoyle’s visage and a stand-up comedian’s vigour, leaving no minority unstoned in a scabrous hail of sarcastic grapeshot: “lobotomised by pornography, a whole generation’s spunked itself into a coma. They’re polishing their cocks instead of polishing their shoes. And then they wonder why we can’t compete with China.”

Winning stuff. The China topicality makes this second run at the Arcola more than welcome but if the West End beckons, a larger playing area and less furniture shifting might help establish the urgent buzz of newsroom atmosphere and speed Jagasia’s dirt-digging plow.

Oh, and the newspaper proprietor needs to be dating Jerry Hall.