Perhaps the best thing you can say about this coming-of-age comedy set in the Kent suburbs is that it has the makings of a decent sitcom. It’s harmless enough, but ropily scripted and hammily acted, even by Britcom standards. And, weirdly for a film supposedly based on actual events – adapted from Dave Roberts’s football memoir about life as a fan of beleaguered Bromley FC during the 1969-70 season – a persistent whiff of fakeness hangs over it.

Brenock O’Connor is friendless, over-confident 15-year-old Dave, whose beloved Bromley are sliding down the league, suffering humiliating 8-0 defeats against the likes of Carshalton Athletic on a weekly basis. The half-arsedness of Bromley’s squad of part-timers is fondly recreated: lardy unfit players dragging themselves on to the pitch, stubbing their fags out as the ref blows the starting whistle. And there’s a sweetly sentimental speech by Dave on the masochistic agony of supporting a terminally awful football team, as he contemplates life after Bromley (“I’ll have to go to Chislehurst Wanderers and they don’t serve tea”).

Everything else is pretty hopeless. The Bromley Boys plays out exactly how you’d expect, as Dave, along with a trio of dim-witted mates from the supporters’ club, hatches a plan to save his club from relegation to the Sunday league. The plot hangs on a misunderstanding over a transfer deal that’s far-fetched even for this kind of light comedy, while Dave lands himself in some monumentally unfunny and deeply implausible scrapes. Martine McCutcheon and Alan Davies, in small thankless roles as Dave’s mum and dad, add to the telly-ish feel (“Show your farva some respect”). The result misses the goal by 20 yards.