Divorces, adultery and the violent death of a princess. Young royals falling out of West End nightclubs; tearful, soul-baring interviews. Compared with all that, David Grindley's revival of Royce Ryton's slow-moving play about the Abdication crisis, first produced in 1972, feels neither exciting nor especially relevant. It's no revelation that the contrast between the traditions of stiff upper lip and devotion to duty depicted in the drama present a marked contrast to today's attitudes. Ryton is firmly on the side of the appalled Queen Mary, played here with stately aplomb by Patricia Routledge, rather than that of her smitten and rebellious son. But there is little exploration of the hypocrisy that underlies inflexible morality, while emotional repression, responsible for so much misery among families in every social stratum, is presented as a virtue.

It's 1936, and there's consternation in Queen Mary's private sitting room at Marlborough House. The American press is agog about the romance between King Edward VIII and the married divorcée they are already referring to as “Queen Wally”. Rufus Wright's Edward, fresh from a European trip with Mrs Simpson, is suntanned, cheerful and full of objectionable new Americanised habits, including a taste for cocktails and enhancements to his vocabulary that his mother regards as vulgar.

Naively, he imagines that marriage to Wallis is perfectly feasible; his mother swiftly sets him straight. The British people, she says, “are fundamentally moral; they will disapprove”. Besides which, as King, and head of the Church, it is constitutionally impossible for him to marry a twice-divorced woman. The rest, as they say, is history, and very dry it seems, despite sterling work from the cast. Routledge is impressive as the Queen, all arid wit and cut-glass vowels. There's a moment, when Richard Hansell as the terrified, stammering Bertie, forced by Edward's abdication to reign as George VI, breaks down and, allowing herself a brief instance of tiny tenderness, Routledge touches his shoulder. Within minutes, though, she's back to proclaiming: “We must all behave as if nothing had happened.” For just a second, we have glimpsed the human cost of her rigid code of honour.

Otherwise, the writing is brittle and overdeliberate. Grindley's production is stagey, but it's difficult to see how it could be otherwise with such dated material. Routledge's legions of fans will doubtless relish a performance that is precise, perfectly controlled and rich in intelligence and nuance. But this dusty old museum piece has little else to offer.

Box office: 0870 0606651, to July 5, then touring

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