Alan Cox gives a terrific performance as Boris Johnson – aka Max Newman MP in this innocuous satire by Robert Khan and Tom Salinsky – but neither he, nor the play, rings remotely true.

In a week when Boris has announced his unsurprising intention to stand as an MP at the next election, Max – already an MP but still basking in his fame as an untouchable Mayor of London – is running for the party leadership after the Prime Minister has stood down.

Not an unlikely scenario, possibly, in a year's time, but the set-up here is implausible. The chief whip, Eleanor (Joanna Bending), has summoned Max and his rival candidate, wet-behind-the-ears Dan (Laurence Dobiesz), to a meeting in a disgraced former MP's office.

Max wants to know why Dan's standing against him and Eleanor wants to know why Max bullied her twin brother at college and possibly drove him to suicide. There's a not too subtle shifting of gears and alliances, until…well, put it this way, is Boris a loser?

The writing's basic, and so is the secondary acting in Hannah Eidinow's production. Cox, though, wrings all he can out of the Boris mix of smug indefatigability and wheedling charm without resorting to impersonation; he's rumpled and rollicking, but the easy manner and glint of steel are all pure Cox and no borrowed feathers.

Kingmaker runs at the Pleasance Courtyard until 25 August