In London you can wait years for a great musical and then two arrive within 24 hours of each other. Hard upon Carousel comes Trevor Nunn’s dream-struck, elegantly scaled-down production of Stephen Sondheim’s A Little Night Music, that extraordinary words-and-music vision of the games and tricks people play when trying to break into or out of love-relations. It all happens in a mythical, far away Sweden, mostly one hot, high summer week-end on a country estate where Maureen Lipman’s ancient courtesan, who boasts of having amply pleasured royalty in her busy past, throws a party for her actress daughter, Hannah Waddingham’s Desiree, who is torn between two husbands, neither of them her own. Would-be or have-been couples, in the form of three sexual triangles, come up against that familiar, irritating obstacle to erotic pleasure — the Other Person.

Based upon Smiles Of A Summer Night, that unusual excursion into the world of comedy by Ingmar Bergman, inspired by A Midsummer’s Night’s Dream and Richard Strauss’s Der Rosenkavalier, Sondheim’s musical, ravished me exceptionally last night. Thanks to the intimate studio surrounds you can hear and relish the pleasure of Sondheim’s mocking, wit-prone lyrics far better than in larger spaces. The fascinating,waltz-bound music, when delectably played by a septet, allows you to appreciate Sondheim’s complex shimmering score afresh — all nervous, erotic energy and most occasional ecstasy.

David Farley’s set primarily depends upon a bare-room setting, with frosted glass back panels that soon look out onto a silver-birched garden estate. This bare, decluttered staging helps give Nunn’s production its attractive, dreamy impetus. The opening scene, in which couples waltz in a mist-enshrined room, sets the mood of midsummer reverie, beset by the itch of sexual frustration. A sense of romantic perspective is given by Lipman’s white-haired, wheel-chaired and constantly amusing Madame Armfeldt who in liaisons views the goings-on with aphorisms and scathing, frosty hauteur, as if minor royalty obliged to attend a lower-class tea-party where the morals appear no more elevated than those of alley-cats. The chief sexual attraction, as far as Waddingham’s attractive but disengaged Desiree is Alexander Hanson’s Fredrik who bears the burden of a virginal, teenage wife, Anne, while his teenage son, Henrik, mopes.

Since Desiree is already immersed with Alistair Robins’s bellicose Count Carl Magnus, the sexual merry-go-round is already set in captivating motion. Sondheim’s lyrics, such as Every Day A Little Death and It Would Have Been Wonderful, characteristically keep heart-felt emotions under wraps. Discovery and self-discovery change everything, even for the more clear-eyed servants, and precipitate the melting down of those sexual triangles. The crucial Send In The Clowns finally forces closure: the beautiful pathos of Waddingham’s rendition is limited by her being too young to sing of being “so late in my career”. Other qualifications apply to some weakly characterised performances. Never mind. A Little Night Music, with its wonderful music of repressed desire, ranks as a rare, serious delight — obviously West End bound.