It’s very likely no person will ever have the same boundless charisma as Paterson Joseph: it makes him the perfect performer to carry off a one-man show, in this case the first play he has authored, Sancho: An Act of Remembrance.

It’s a loving excavation and a playful ‘act’, written deftly enough that others could – and should – take on this role themselves, but you’re almost reluctant to imagine anyone else in this role. Ignatius Sancho, the first Black Briton to vote in a general election and to have an obituary in the British press, a man of letters, a novelist, an abolitionist. While seeing Sancho as the symbol he was in the eighteenth century and still is now, a representation of our past ignored in schools (though beginning to be taught now) and a spit in the eye for David Starkey’s whitewashed view of history, Joseph is also sensitive to Sancho as a real person who existed, deserving of respect. The details of life are delivered to us as he might have, mundane and fantastic alike, to create a portrait of the whole man to accompany the one he poses for onstage.

And, before us, he lives a life. He endures indignities, sees something of truth and beauty in the acting of David Garrick and as he learns to read, and towards the end of his life has the relative ‘privilege’ of struggling financially, with his large family, as the owner of a greengrocer’s shop. Sancho was anything but mediocre, but certainly in his treatment by his contemporaries and his difficulties finding practical security he well exemplifies the lie of the ‘Exceptional Immigrant’ we still face down today. Sancho was given a chance of which too many others were deprived, and his anger at the bondage of his fellow men is presented by Joseph as partly because he knows how nearly he escaped a similar fate.

Joseph transforms himself – it is as if he grows a belly he does not have; he makes froglike eyes bulge out of nowhere to convey Sancho’s childhood, cosseted and kept by three rich spinsters in Greenwich. His voice seems to manipulate the beautiful space of the Wilton’s Music Hall to whatever end he desires. Joseph created Sancho, he tells us, resentful that his “white contemporaries” were allowed to act in costume dramas, and the audience, still, is comprised more of these white people than anyone else.

A greater resonance might have been achieved by his altered version of the play had the audience been not been of this type (white and well-off): the emphasis here is on that moment of Sancho’s historic vote, and how without the vote, so easily denied, a person is no more than a “slave”. Joseph’s accent and speech impediment as Sancho drops away and he notes he is not an actor in a play, not when it comes to this. Seeing Sancho has been a longstanding dream of mine, and I find myself a little disappointed to miss out on seeing Joseph as Sancho’s wife, Anne Osborne, after her husband’s death.

The same sense of our debt to history and continued struggle for liberation for all is achieved, however. Everyone should see Sancho – not least because it’s ‘important’, but for Joseph’s skill as actor and writer, for this assured theatrical event itself.

Sancho: An Act of Remembrance is playing at the Wilton’s Music Hall until 16 June

Photo: Robert Day