Chief examiner Mr Burgess, played with thrilling comic cruelty by Steven Pacey, sets his latest cohort of four would-be London Taxi drivers the task of committing to memory all 320 routes, 15,842 streets and all places of interest on the way within a six-mile radius of Charing Cross. “No taxi driver in no other city in no other country in the world has to know a fraction of what you have to know. And not many brain surgeons neither.” The late Jack Rosenthal’s 1979 play for TV exploring the impact of this almost impossible challenge (70% drop-out rate then and some 25,000 streets now) is adapted for the stage by Simon Block and directed with comic verve by Rosenthal’s wife for 30 years Maureen Lipman, who appeared in the TV drama.

It’s a challenge that takes over every aspect of the aspiring cabbies’ lives as well as those of wives and girlfriends. The sacrifices provide the dramatic tension and much of the comedy. Simon Block channels Jack Rosenthal’s ability to imbue what might otherwise be comic stereotypes with genuine warmth and humour by homing in on the self-knowledge his characters acquire along the way. Wisely he does not attempt to deal with the television version’s affectionate paean to the streets of London or to update it. The parallels with today’s struggles for the man on the street are evident.

Ex-Eastender James Alexandrou invests Jack-the-Lad Gordon with a swagger and cockiness that doesn’t get entirely beaten out of him, even by his long-suffering wife Brenda (Celine Abrahams, abrasively assertive). Ben Caplan’s funny, heartbreaking Ted, with his photographic memory and desire to keep up the family tradition of go-to droshky drivers, is the sure cert to get his Green Badge, encouraged by his loving, supportive wife Val, whom excellent Jenna Augen invests with touching eagerness. The ‘one most likely to fail but you know he won’t’ is Fabian Frankel’s engaging nebbich teenage Chris, who physically and metaphorically undergoes the greatest personal transformations, egged on by girlfriend Janet. Alice Felgate invests her with a wonderfully sympathetic no-nonsense briskness that warms the stage.

Louise Callaghan brings a defiant laddishness to chain-smoking Miss Stavely, the sole female candidate. She feels a tad underwritten, perhaps because as a proudly independent young woman in a man’s world, she has no partner, supportive or otherwise.

Mr Burgess’s torture chamber/office dominates Nicolai Hart-Hansen’s split-level stage as his efforts to force his examinees off the road by questioning them with inhalers stuck up his nostrils or doing press-ups dominate the action. “Compared to people, The Knowledge is a piece of marzipan. They mumble. They can’t hear you. They don’t know where they want to go. They get up both your nostrils”.

By Judi Herman

Photos by Scott Rylander

The Knowledge runs until Saturday 11 November 7.30pm, 2.30pm (Wed only), 3pm (Sat only). £17.50-£42.50. Charing Cross Theatre, WC2N 6NL. 084 4493 0650. http://charingcrosstheatre.co.uk