‘What’s your favourite colour?’ asks 15-year old Minnie Goetz (Bel Powley) as she lies naked, post-coital alongside her mother’s thirty-five year-old boyfriend Monroe (Alexander Skarsgard). It’s a situation which perfectly sums up THE DIARY OF A TEENAGE GIRL, the diary being recorded on a bulky cassette recorder and hidden under her bed. It’s 1976 in San Francisco and hormone-rich Minnie is charging full tilt at life, specifically sex, drugs and rock-and-roll (or Mott the Hoople, at any rate).

Not that Minnie’s life isn’t complicated enough already, struggling along with her little sister Gretel (Abigail Wait) as they are brought up fitfully by their feckless and hippy-ish mother Charlotte (Kristen Wiig) whose job in a library we sense isn’t destined to last long, given her own adolescent taste for cocaine-fuelled partying. Minnie and Gretel are also subject to oppressive encounters with their wealthy stepfather Pascal (Christopher Meloni), looking on bitterly as his ex-family goes to hell. Left to her own devices, Minnie faithfully records her coming-of-age experiences on tape: graphic sex with her best friend Kimmie (Madeleine Waters) including a scene of them both on their knees in front of two boys in a hotel room, chastely holding hands as they beaver away. A bad idea, they both agree later.

But Minnie has an extra dimension which the movie exploits to the full (luckily, as the voice-overs tend towards repetitiveness): she’s a would-be artist in the vein of R.Crumb and his wife Aline Kominsky. So alongside the taped diary Minnie illustrates her life in cartoons in the Crumb family style and corresponds with the encouraging Kominsky who becomes an animated presence on the screen, accompanying her down the street: this and the other visual flourishes by Sara Gunnarsdottir (ironic Disneyesque love-birds etc) also help realise Minnie’s inner emotional life besides adding to the richly detailed period flavour, a mixture of Keep on Truckin’ and The Joy of Sex.

Not that Minnie’s life isn’t complicated enough already

Central to DIARY OF A TEENAGE GIRL though is the relationship between Minnie and Charlotte, driving the narrative along through affection, frustration, anger and recrimination at the inevitable discovery of the diaries – all the traumas of an adolescent life with Mom in other words – which recalls A TASTE OF HONEY in its sense of family rubbing along through thick but mainly thin and coming to a brittle arrangement. In Shelagh Delaney’s play and film Jo the daughter becomes pregnant; here the dangers in pre-AIDS San Francisco are less long-term, booze and bad acid trip-based and mainly limited to Minnie’s fervid imagination (wondering what it would be like to be a prostitute for example) – it seems that in her adaptation of Phoebe Gloeckner’s graphic novel, the writer-director Marielle Heller winnowed out darker passages involving Minnie and Kimmie’s sexual explorations, somewhat in the way David Lean’s version of GREAT EXPECTATIONS ignores Pip’s losing his fortune towards the end in the interests of not over-complicating the plot.

But what remains is a great piece of work, and DIARY OF A TEENAGE GIRL too works very well on its own self-confident terms. First-time director Heller (also an actor) elicits strong performances from the principals, in particular Kristen Wiig who grabs the dishevelled Charlotte with both hands, a Mrs Robinson in reverse. As for the luminous Bel Powley: anyone who can carry off Minnie and Princess Margaret (in A ROYAL NIGHT OUT) in consecutive movies is a talent not to be trifled with.