The Queen and Margaret Thatcher are becoming a familiar theatrical double act. They provided the sparkiest encounter in Peter Morgan's The Audience. Now Moira Buffini has expanded a short piece she wrote for the Tricycle's 2010 project, Women, Power and Politics, into a full-length play; and the result, if occasionally overstretched, provides a very funny portrait of a relationship between monarch and prime minister that clearly wasn't made in heaven.
Buffini's brightest idea is to double the central roles. So we get an older and younger Queen, respectively known as Q and Liz. Equally we get an older and younger Thatcher, identified as T and Mags. Add in two male actors playing 17 other roles, ranging from Kenneth Kaunda to Rupert Murdoch, and you have what sounds like a recipe for confusion. In fact, Buffini's device gives the whole evening a buoyant, meta-theatrical playfulness. The older Q spends much of the play trying to hustle the action along in order to get to the interval. And the two Thatchers, while consistent in their detestation of socialism, often lapse into a good cop/bad cop routine that says a lot about the late PM's contradictory techniques.
The difficulty is that no one knows what transpired at the weekly meetings of sovereign and minister. But Buffini creates a wholly plausible conflict of values between two radically different women. In July 1986 the Sunday Times published a front-page story itemising the monarch's dismay at her "uncaring" government. And, given the Queen's attachment to the Commonwealth, it seems highly likely that she discreetly expressed her views on such subjects as Thatcher's foot-dragging acceptance of majority rule in Zimbabwe or unwillingness to apply sanctions to apartheid South Africa.
The play is obviously speculation. But behind the jokiness lies a tight-lipped collision between two women who entertained opposing ideas of Britain's role in the world.
As in all plays about the monarch, from Alan Bennett's A Question of Attribution onwards, the Queen comes out on top. Precisely because her constitutional powers are limited, she has to express herself obliquely. And Marion Bailey is quietly hilarious as the older Q, whether showing her displeasure at being lectured by her first minister or slyly pointing out that it was a Murdoch paper that splashed their supposed antipathy. Even if Clare Holman as Liz has less juicy lines, she also registers an unforgettable stony blankness at being asked if she's read Hayek's The Road to Serfdom.
Fenella Woolgar as Mags and Stella Gonet as T also join the long list of expert Thatcher impersonators. The former combines dogmatic certainty with a low-register voice that seems to be filtered through a vat of honey: the latter is the more familiar later Thatcher who grows more strident as she feels power slipping away from her. Neet Mohan and Jeff Rawle play the plethora of male characters in a production by Indhu Rubasingham that is perfectly pitched between the comic and the serious. The play has odd duff moments, especially in the scenes involving the broadly caricatured Reagans. It offers, however, a fascinating fictional portrait of two women who had much in common, such as their age and imperviousness to physical danger, but who were also separated by what seems like an unbridgeable chasm in which monarchical emollience regularly confronted ideological inflexibility.
• Join in a post-show Q&A session with Moira Buffini after the 8 October performance of Handbagged. Go to theguardian.com/extra for more.