Marlon Brando’s reputation as an actor has scarcely diminished since his triumphant emergence in the post-war years. Opinions about the man himself have, however, been in a constant state of flux. Was he psychologically troubled or just lazy? Was he a radical or a tinfoil hat crank?

We get some clues in this extraordinary collage from British film-maker Stevan Riley (whose best-known film has, to this point, been about West Indian cricket, of all things).

Made with the co-operation of the great man's estate, Listen to Me Marlon is structured around private tape recordings that find the actor musing on every aspect of his life. At times, he is involved in self-analysis and self-hypnosis.

Elsewhere, he seems to be treating the recording as a diary. It is hard not to place the later words in Colonel Kurtz’s mouth as he sits madly alone waiting for state-sponsored nemesis. The insights concerning his father are particularly striking. “One time my old man was punching my mother,” he says. “And I looked at him, and I fucking put my eyes right through him and I said: ‘If you hit her again, I’m going to kill you’.” The speaker is, remember, a man whose own son Christian – perhaps over-indulged – was later jailed for killing his half-sister’s boyfriend. This is not a comfortable psyche to dip into.

For all the fascinating and occasionally disturbing musings, Listen to me, Marlon is missing contrary voices. The archival material exists in a vacuum, with no mediation. There is a purity to such an approach, but one finds oneself longing for an onscreen presence to lean against the weighty mass of ancient musings.

Any disentanglement of Brando’s private life would, most likely, be beyond even the most talented documentarian.

But the question of why he made so many bad professional choices – mentioned here, but not properly explored – surely needs more serious investigation. This remains, nonetheless, an essential document for anybody even peripherally interested in this great, mumbling enigma.