Upstairs at the Gatehouse is staging a sell-out show about musical - and maths prodigy - Tom Lehrer.

Starring Shahaf Ifhar as the US singer songwriter,  Tom Lehrer is Teaching Math and Doesn’t Want To Talk To You is written by self-confessed Lehrer nut Francis Beckett, whose plays have become familiar to audiences at the Highgate venue.

Lehrer was born in 1928 and was quickly recognised as a mathematics, sorry, math prodigy.

At 15 he was accepted into Harvard, graduated at 18 and took his master’s a year later. Then he spent sixteen sweet years enjoying campus life, becoming a researcher at Los Alamos and writing some of the sharpest and funniest songs in the American repertoire.

Ham & High: Pianist Harry Style plays Lehrer's repertoire including the incomparable The ElementsPianist Harry Style plays Lehrer's repertoire including the incomparable The Elements (Image: Simon Jackson)

Beckett tries to answer why, at the age of forty, at the height of his fame, he turned his back on entertainment and spent the rest of his career as a maths lecturer.

The result, which has sold out its Highgate run is a glorious celebration of one of the brightest, wittiest and most principled satirists.

Beckett tries to answer his central question via two fictional journalist interviews.

Nabilah Hamid (excellent as Iris, but struggling with a thin script) provides the chronology of Lehrer’s fascinating life while repeatedly asking why, why, why?

The amazing Shahaf Ifhar has nailed the voice, mannerisms and character of Lehrer: self-effacing, grounded, big-brained, a tad patronising and acutely aware of his limited ability to change anything.

Pianist Harry Style’s accompaniment is great but, as Lehrer usually performed sitting down at the ivories, it does prompt the question what he was doing there?

Ifhar’s delivery of so many old favourites delighted the enthusiastic and knowledgeable audience: Lehrer would have loved the sing-a-long of We will all burn together when we burn.

Two dozen favourites were performed with a knowing subversion and gusto; Poisoning Pigeons in the Park, The Vatican Rag, Pollution, Hanukkah n Santa Monica and finishing with the extraordinary The Elements.

Does Beckett find his answer?

Not really, but maybe it wasn’t a very good question in the first place. I don’t think anyone knows why the Beatles broke up, but I love documentaries that ask why: and the soundtrack is always so good.

Tom Lehrer is Teaching Math and Doesn't Want To Talk To You runs until June 9.