Released to coincide with Windrush Day, this engaged drama-documentary pays tribute to Ulric Cross, the Trinidadian who became the most decorated of the RAF’s West Indian recruits during the second world war; he later became a producer-presenter with the BBC, then a go-between in several African countries’ struggles against imperialism.

From the off, writer-director Frances-Anne Solomon strikes a wistful note, wavering between celebration of an extraordinary existence and regret around the aims unachieved in that lifetime. Footage of the actual, ailing Cross prompts daughter Nicola to remark that, to winkle these details out, “it’s just so silly that it takes some dying”. As Britain re-examines where it stands in relation to the Windrush arrivals, it is timely viewing, to say the least, though it finally offers an even bigger picture than that suggests.

Solomon’s reconstructions raise complicated questions of identity that a better furnished period drama might stifle among its scatter cushions. An RAF application form prompts reflection on whether Caribbean fliers felt more African or European in their outlook. In postwar London, Cross (played by the quietly commanding Nickolai Salcedo) lives a dual life, meeting with such thinkers as CLR James and George Padmore, yet hiding their words from his white British sweetheart Anna (Pippa Nixon). He makes for an atypical biopic subject: more analyst than man of action. Evidently, Cross saw Britain backsliding into complacency after vanquishing the Nazis; a further tragedy is how Africa, which Cross viewed as a possible promised land, came to be riven with murderous uncertainty.

Those African travels – encompassing a plot to smuggle Padmore’s papers out of Ghana – allows Hero to flirt with commercial thriller territory, but it is largely a film of meetings and discussions, intuiting that backroom talk is what most often alters the course of our lives. Solomon’s clever marshalling of archive footage gives it scope, repositioning Cross in the middle of a monochrome world only reluctantly converting to Kodachrome and Technicolor. Inevitably we see Lord Kitchener, cuddly enough to be integrated into the Paddington universe. More shameful is the unveiling of a “Keep Britain White” banner in Trafalgar Square, forcing the protagonist into a decision presumably now facing many foreign nationals. The film gets episodic late on, yet remains stimulating and provocative – filmed history that means to prompt debate, rather than light matinee snoozing.