This is a perfect piece of theatre. Miles Jupp sails seamlessly through James Kettle's exquisite writing. This is a finely balanced filigree of comedy and tragedy. Jupp moves from humour to sadness, to wistfulness to bombast, and back over all three, effortlessly. He is magical. Based on the life of David Tomlinson, the actor best known for playing Mr Banks, the father in Mary Poppins, The Life I Lead (the title taken from one of the songs in the film) explores the extraordinary real life of the actor, who was a pilot in the Second World War. In this one-man show, Jupp also plays, among other character, Walt Disney who gave the actor his most famous role and the actor's father, Clarence, a remote figure who the play reveals had a secret second family with seven other children. Clarence's first family only discovered the truth because one of David Tomlinson's brothers was sitting on the top deck of a bus when he saw through an upper window, his father eating kippers in bed. Clarence Tomlinson was what Jupp has described as a "cold-eyed barrister". A highlight of this magnificent piece of acting is when Jupp plays Clarence defending his son David in court, after the latter has crashed a Tiger Moth plane in civilian life because he blacked out when flying it. He also plays the ancient judge who hasn't heard of any of the younger Tomlinson's films. The facial contortions - the aging simply with an expression is unforgettable and a joy to see. Jupp opens this one-man show by modestly stepping onto the stage and apologising. "If I am interrupting anyone's evening". He is the quintessential bumbling Englishmen. He then gently unfolds the story of Tomlinson's life: his remote father (who he says was obliged to be distanct since he was running two families). His first wife's suicide, reminiscent of a Greek tragedy. Ten years later his falling in love at first sight with his second wife, the actress Audrey Freeman. The mystery condition of one of their four sons and his touching pride in the little boy's eventual achievements. Jupp's performance is a subtle masterpiece, a triumph of powerful understatement. It is storytelling at its finest and a world created which is funny, moving and unforgettable. The Life I Lead is at Cambridge Arts Theatre until Saturday, September 14, after which it will move to Wyndhams Theatre in London's West End.