It's hard to imagine any person – even somebody entirely immune to dad rock – failing to derive amusement from this documentary on the great drummer Ginger Baker. It is, however, reasonable to ask if any fool could have made a decent film just by pointing a camera in Ginger's direction.

Now 73, permanently shrouded in cigarette smoke, Baker spits furiously from his chair like the most annoying ancient in the seediest pub on the roughest estate. Over the course of the story, as wives are discarded and fortunes squandered, he emerges as a casual misogynist, an intolerant collaborator and an unreliable witness. Sacred monsters have rarely been quite so monstrous. But the film also manages to convince us of his talent and taste for innovation.

Originally a jazz drummer, Ginger helped invent British rock with the Graham Bond Organisation before going on to conquer the paisley universe with Cream and Blind Faith. He later became a pioneer of world music (as it then wasn’t called). Trivial comparisons are made with John Bonham and Keith Moon, but the assorted talking heads – including the subject himself – hurriedly explain that Ginger is in a different class altogether. The footage confirms that assessment.

So, Jay Bulger, a Rolling Stone journalist, certainly has an irresistible subject on his hands. The director is, however, to be congratulated for organising his material with a great deal of zest and originality. On occasion his off-screen questions suggest Marty DiBergi from Spinal Tap – "You feel like a preserved moose," he doesn't quite say – but the friction between interviewer and interviewee adds real tension to the piece. For all the banter between Richard Nixon and David Frost, the president never resorted to biffing his interlocutor on the nose. Mr Bulger does not get off so lightly.

As is often the case with such projects, the material covering the long years of obscurity is less interesting than the celebrations of life as a young butterfly on the wheel. But contributions from the likes of Charlie Watts (dry), Jack Bruce (weary) and Eric Clapton (surprisingly likable) keep the story buzzing throughout. Imaginative animations punctuate the chatter.

Essential stuff for both old bores and young idiots.