There's no better set of songs on the London stage than Irving Berlin's for Call Me Madam, a 1950 musical written for Ethel Merman in the wake of a coarse-grained Washington DC party-giver, Perle Mesta, being appointed American ambassador to Luxembourg.

The second act contrapuntal duet for Sally Adams, “the hostess with the mostest,” a wealthy Texan heiress, and her diplomatic sidekick, Kenneth Gibson, who’s fallen for the Lichtenburg princess, is a complete blast.

In fact, “You’re Just In Love,” with its brilliantly entwined melodies of rhapsody and critical reassurance, is one of my all-time favourite musical theatre items; it’s performed here with bewitching pezazz and glazed charm by Lucy Williamson and Leo Miles, understandably thunderstruck by Natalie Lipin’s Idina Menzel-like princess.

Michael Strassen’s production is a model of small-scale tact and invention, set on a bare stage with curtain-like drapes and a single baby grand (played by musical director Ross Leadbetter), and a lively cast of embassy staff, diplomats and European peasants.

Lucy Williamson and the company of Call Me Madam
Sally falls in love with the Lichtenburg head of state (Gavin Kerr) and nearly scuppers her chances by proffering a $100m diplomatic gift, misconstrued as a colonial overture; the slightly stilted but unjustly maligned book by Howard Lindsay and Russell Crouse maintains a humorous balance between romantic and political self-interest, and even has a few good jokes.

The show’s certainly much more fun than it was in the last, slightly tacky West End production 30 years ago, with Noelle Gordon and Basil Hoskins, and it’s nothing but sheer pleasure to hear songs like “It’s a Lovely Day Today,” “The Washington Square Dance” and “The Best Thing For You” performed, unadulterated by amplification, at such close quarters.

Mark Smith’s delightful choreography (notably in “The Ocarina” which opens the peasant fair) and Chris de Wilde’s design maintain a high level of good taste and appropriate style.

But the show is carried by Lucy Williamson, who possesses the Merman role as of right, not with too much camp impudence, but with a glorious tonality and just the right mixture of sassy vulgarity and winking, lubricious intent.

She’s lovely, and loveable, too, which is perhaps not even something you could say of the late, great Merman, whom I once saw storm the London stage in concert at the London Palladium. Merman was all brass, but Lucy’s an oboe, too.