"Whatever we say must remain between these three walls," says the Queen to Margaret Thatcher in Moira Buffini's hilarious, meta-theatrical development of her own short sketch in the Tricycle's Women, Power and Politics programme three years ago.
You would have thought we'd run out of things to say or to think about the relationship between the iconic female heads of state and government, especially after Helen Mirren's double whammy of The Queen and The Audience (and there are lots of crossover points between this play and Peter Morgan's scripts) and the sensational performance of Meryl Streep in The Iron Lady.
Almost as a rider to that last movie, Stella Gonet's senior Thatcher reminds us at the end that you don't die of dementia, you live with it. And the central relationship of the two women is developed through the weekly audiences and their guarded, growing mutual respect.
But in having two Queens (Marion Bailey and Claire Holman) and two Thatchers (Gonet and the show-stealing, utterly brilliant Fenella Woolgar), Buffini can toy – and this play is nothing if not delightfully ludic – with inner and outer thoughts, reflections and reactions, private and public personae, performance and reality.
Bailey and Gonet present the outer steely facades – one foursquare and frumpish, the other glacial and emphatic – of Q and T, while Holman and Woolgar suggest contrasting, detailed studies in hesitant humanity and studiously maintained certainty as Liz and Mags.
And around them, Neet Mohan and Jeff Rawle as Actor 1 and Actor 2 play a dazzling array of quick-change characters: footmen, the Reagans (Mohan in smart drag as Nancy), Lord Carrington and Denis Thatcher, Neil Kinnock and Rupert Murdoch, Enoch Powell and Kenneth Clarke, Michael Heseltine and Kenneth Kaunda.
These "turns" serve a narrative outline following Thatcher's first election victory in 1979 (and her first audience at the Palace; she waits for a chair and the Queen drags one on herself – ""I've gawn and brought it nah, sit dahwon") to her resignation in 1990, each woman closer to the other and wiser in herself, you feel.
The Audience was marvellous, but this is rougher, funnier, more satirical stuff, almost harking back to the "good old days" of the Private Eye shows such as Mrs Wilson's Diary, or Anyone For Denis, both written by the late John Wells.
And there are unexpected moments of passion, too, as when Thatcher patiently explains her conviction politics ("Attila the Hen," chuckles Q), or Neil Kinnock delivers his "I warn you" speech on the eve of the 1983 election; this follows Arthur Scargill's explosion about the pit closures, which Jeff Rawle commandeers as a personal statement by an actor; the other, younger actor, Mohan, can ask, "What's a closed shop?" to indicate how far we've either come, or regressed.
Indhu Rubasingham's careful, clever and always enjoyable production is designed by Richard Kent as a conceptual outline of Buckingham Palace incorporating Union Jack motifs, but the end result is an elegant arrangement of white trellis, an ideal setting for a series of satirical riffs on the historical background to the Falklands War, the Brighton Bomb, the miners' strike, the poll tax and the fairy tale royal wedding which, like so much else in the period, went horribly wrong.
Keen to find out more about one of the stars? Read our interview with Fenella Woolgar here