Rocking velvet suits and paisley shirts, David Tennant brims with charisma as radical Scottish psychiatrist RD Laing.

This is a fictionalised biopic of the 1960s so-called ‘acid Marxist’, who gave his patients LSD and challenged the medical establishment with his unconventional views on how the mentally ill should be treated.

The focus is on Kingsley Hall, the non-hierarchical community Laing ran in East London from 1965-70, and on his relationship with Elizabeth Moss’ American PhD student (a composite figure).

The movie is distinctly uneven, but it is fascinating and there are a number of standout scenes, including one in which Laing breaks through to a young mute patient (Lydia Orange) in her padded cell.