The return of Chiewetel Ejiofor to the London stage - this is his first performance since Othello at the Donmar Warehouse in 2007 - shows him in high classical mode, large in presence and voice, as imposing and substantial as Lenny Henry in Fences.

Ejiofor is a good deal younger than Henry – 15 years younger – but, like him, he's entered the rich, authoritative middle period of his career, and his portrait of Patrice Lumumba, the political and resistance leader in the Congo, and the independent country's first prime minister in 1960, is a powerful Shakespearean performance in a Brechtian epic.

Film director Joe Wright follows his theatrical debut (at the Donmar) with Pinero's Trelawny of the Wells in fine style: this is a teeming, noisy, colourful, angry show that tells a cracking, if depressing, story of colonial politics and unleashes a tumult of talent in its cause.

The play, written by the Caribbean polymath Aimé Césaire in 1966, is an unanswerable critique of Belgian colonisation, and the political activities of other Western governments in the region (any day now David Cameron will no doubt be apologising for MI6's alleged involvement in the assassination of Lumumba in 1961; this led to 30 years of brutal dictatorship in Joseph Mobutu's re-named Zaire).

But the touch is light and satirical: Mobutu appears in Daniel Kaluuya's nicely edged performance as a participant in the Lumumba government, the Belgian officials as comic policemen with little piggy noses, other politicians as life-size puppets (by Joe's sister, Sarah, at the Little Angel Theatre) and the intermediary UN secretary general, Dag Hammarskjöld, as a turncoat black brother (Kurt Egyiawan) in a hilarious Andy Warhol wig (Dag was a balding Swede).

Ironically, Hammarskjöld also died (in a plane crash) in 1961, but that's another play… like a good guy version of Brecht's Arturo Ui, we see the rise and rise of Lumumba, from beer salesman to prime minister, through scenes of political pastiche and satire, explosive theatrical imagery and, most importantly, the tidal wave of rhetoric in his public speeches.

This is where Ejiofor comes blazingly into his own. For, unlike Ui, this man – and, you feel, this actor – is saying what he really means, and it's a thrilling collision with the audience. Grey-suited, bespectacled, dynamic, full of expressive gestures and stage-embracing physicality, there are moments when Ejiofor resembles Malcolm X as much as the leaner-looking Lumumba.

But the play itself (backed up by an unusually informative programme) should prove essential and rewarding viewing for the Young Vic's young audiences.

They will marvel, too, at another "instant" black theatre ensemble including Joseph Mydell as the Congolese president, Brian Bovell as a Katangan secessionist leader, Sharon Duncan-Brewster as a steaming city bar proprietor and the serene, beatific Kabongo Tshisensa as a civilian percussionist, the very soul of a nation.