James Corden needs to be superlatively good to carry this show: make no mistake, Francis Hensahll, the “one man” of the title, is onstage virtually the whole time, and he carries a lot of plot and jokes on his shoulders. Lucky, then, that Corden imbues Francis with the energy to make him a  rogue while adding just enough pathos to keep him likeable. He is an extremely talented clown, adept at manipulating his audience and making sure we are rooting for him as he begs, borrows and steals his way from rags to, well, not riches, but at least a good dinner and a trip to Majorca.

The audience in the Lyttleton on a Sunday afternoon was kind to Corden – perhaps a little too ready to laugh: there is a tendency to be prepped to laugh when we know we are seeing a comedy and that a well-known comedian is in the title role. This can mean that the jokes don’t necessarily have to hold up to much scrutiny, they just need to be delivered by the right person. As I say, I have no doubt that Corden was the right man for the job, but I am not convinced that the jokes would fare as well in less capable hands.

Richard Bean has taken Carlo Goldoni’s The Servant of Two Masters and dragged it into the 1960s, complete with Beatnik actor-wannabe, a beehive-sporting proponent of Women’s Lib and a wonderful be-suited skiffle band. There are moments when the script could be sharper, but it has some nice flourishes and enough genuinely funny nods to the time to keep the punters happy. Dolly (Suzie Toase) declares at one point that in the next 20 years there will be a woman in 10 Downing Street and that caring for the poor, compassion and an end to foreign wars cannot be far behind. It’s adeptly done, but overall Bean’s script is not quite as deft as it could have been.

His characters remain a little two-dimensional, too. Pauline (Claire Lams) is thick. That’s about all we learn about her, through no fault of either Lams herself or Nicholas Hytner’s direction. Her wayward fiance, Alan (Daniel Rigby) is an Actor with a capital A, and flounces a lot. He is very funny, but  rather a slender character. Diminutive Jemima Rooper as Rachel/Roscoe is genuinely intimidating, and plays with a lightness of touch missing from some of the other cast members – she doesn’t become a caricature despite not being given a great deal to work with. Oliver Chris as Stanley is furiously channeling Hugh Laurie’s Bertie Wooster for much of the show, with a few more boarding-school jokes thrown in for good measure. He is hilarious, but one can’t help but wonder what the fiesty Rachel sees in his ugger-bugger Stanley.

Grant Olding’s musical interludes are wonderful: they set the mood nicely and provide entertainment during the scene changes. However, they become increasingly frequent and more bizarre as the show goes on, until it inexplicably turns into a musical in the last five minutes, as if Bean didn’t know what else to do with his story and demanded a big ensemble number as a finale. The cast have serviceable voices, including Corden, but it all gets a bit silly towards the end. The skiffle band, however, are great – good musicians and personable performers, and I enjoyed Corden’s turn on the metalophone wearing a rather natty fez.

The piece is predictable enough, but Bean/Goldoni work in enough clever set-pieces to keep it pacy, expertly directed by Hytner. The humour is slapstick in the extreme, and the fourth wall is broken frequently and with impunity. All-in-all it’s a silly, cheerful vehicle for Corden to clown – which he does superlatively well.

One Man, Two Guvnors is playing at the National Theatre until 19th September. If you’re under 26, you can get £5 tickets for the show. See the website for more information.