This big-hearted musical comedy started life on the stage in 2017 – and 10 years before that as a TV documentary about the true story of gay teenager Jamie Campbell, whose dream was to be a drag queen. The broad characterisation, dialogue and scene transitions probably worked better on stage, but they give a bounce to this feelgood Britfilm version, which has newcomer Max Harwood as Jamie, Sarah Lancashire as his tenderly understanding mum Margaret, and Lauren Patel as his best mate Priti; Sharon Horgan has the thankless task of playing the uptight teacher who won’t let Jamie turn up to the school prom in drag, while Richard E Grant has a scene-stealer as Hugo Battersby, AKA “Loco Chanel”, a veteran drag queen artiste who campaigned against homophobia in the 1980s and who mentors Jamie in his new vocation.

In some ways, Everybody’s Talking About Jamie conforms to a template that’s been around in British cinema for years, or in fact decades: Jamie wants to be a drag queen in the way that he might in previous stories have wanted to be a ballet dancer, or even train a kestrel. It’s also part of an honourable film tradition of building a better life through showbusiness, as in The Full Monty. In the classroom, Jamie has a withering contempt for the civilians, muggles and dullards who presume to mock him and make homophobic remarks – and as far as post-school goes, he certainly convinces you that the really shallow and tragic career choice is going for the straight world of office and call centre. Grant gives a nice performance; his drag persona has hair that looks like a certain 1980s-era prime minister.

• Everybody’s Talking About Jamie is released on 17 September on Amazon Prime Video.