What do most people know about the Isle of Man? Birth-place of Mark Cavendish, sometime home to Nigel Mansell and Jeremy Clarkson, motor-cycle races where riders invariably die, strange attitude to homosexuality, Parliament with an un-remembered name. Er…that’s about it.

And now to add to the list; setting for Mindhorn, a new British film.

Mindhorn was a fictional, fictional (ie it imagines something that never happened which never happened) TV detective series from the 1980s, starring Richard Thorncroft as Mindhorn who had an artificial eye which enabled him to see the truth and thus solve crimes. Now, Thorncroft is washed up, on his uppers, living in Walthamstow (poor chap), auditioning for parts as a middle-aged Jamaican in front of Kenneth Branagh (playing himself) and hassling his agent for work, having been dropped from his gig advertising ‘thrombi-socks’ and male girdles in favour of John Nettles (oh, the shame, the horror).

Meanwhile, back on the Isle of Man, a murderer  – calling himself the Kestrel (for reasons that aren’t entirely clear) – is taunting the police, refusing to talk to anyone other than, yes you guessed it, Mindhorn.

And so, Thorncroft returns to the Isle of Man, in character, seeking redemption, resurrection of his career and the chance to re-live old glories with former girl-friend, Pat Deville, played by Essie Davis

This mildly amusing (and that’s not meant as a criticism), sweet-natured, gentle film is enjoyable and passes the time most agreeably. There is a host of second-string British character actors whom you recognise from Midsummer Murders or Lewis but can’t quite put a name to and the Isle of Man provides a pleasant background without making you feel you need to catch the next boat to go there.

Steve Coogan appears as Peter Eastman who appeared in Mindhorn and then launched ‘Windjammer’ a spin-off series from Mindhorn and his career has followed a different arc to that of Thorncroft. Coogan doesn’t quite fit in the film – he’s better known than the actor (Julian Barratt) who plays Thorncroft but here he’s a bit-part player who seems unsure of how to play his character and the success of Windjammer is never explained.

The denouement is a bit silly and most everyone emerges alive and lives happily ever after but that’s in keeping with the real (fictional) Mindhorn – as is the rest of the film.

There are nods to other programmes – the whole ‘nutter obsessed with a TV character’ has been done before, most recently in an episode of I’m Alan Partridge (Coogan’s star vehicle); Thorncroft’s  bid for pop stardom with his hit ‘You can’t hand-cuff the wind’ (playing, with video, over the end credits) is uncomfortably close to David Brent’s attempt at pop stardom in Ricky Gervais’ Life on the Road, while his need for a girdle echoes Gervais’ audition scene in Extras. At one point Thorncroft gets off his face on cocaine and scrawls obscene graffiti on Clive’s car; a scene which mirrors the ‘Cock, Piss, Partridge’ episode in I’m Alan Partridge.

Julian Barratt is fine as Thorncroft, capturing his character’s melancholy while simultaneously grasping his chance of redemption and he slips brilliantly in and out of character as Mindhorn: Simon Farnaby (who wrote the film along with Barratt) plays Mindhorn’s former stunt double, Clive Parnevik, with an odd South African accent, while Essie Davis is, at the wrong side of 40, still stunning as Mindhorn’s former squeeze, now unhappily married to Clive. Andrea Riseborough appears as a police-woman dressed in leathers like Diana Ring in the Avengers (for those with long memories) and does her best with an under-written role.

This is a fine little British film which doesn’t take itself too seriously that deserves to find an audience. A bit like the Isle of Man.