"The history plays are super-boring," complains Queen Margaret of Anjou. And she should know: Shakespeare wrote her into four of them, including one scene – in Richard III – set when the real Margaret was dead. This quick-witted, irreverent one-woman shows aims to reclaim her true life story, and uses it to make adroit and important points about women's experiences in our own day.

Gillian English's portrayal of the late-mediaeval queen isn't exactly faithful. She plays Margret as a brash American millennial – loquacious and confident, with a deep-rooted sense of entitlement lurking just beneath the surface. At one point, she even sends her fellow monarchs a round-robin email. But the story she's telling is a genuine one, planted firmly in fifteenth-century England; my fact-checking is limited to a quick skim of Margaret's Wikipedia page, but as far as I can make out it all appears to be true.

English's monologue feels free-wheeling and spontaneous, full of detours and apparent digressions, yet ultimately they all prove central to the messages and plot. She plucks amusing, off-the-wall imagery seemingly from the air, whether she's comparing the Wars of the Roses to an Australian barbecue or the King of England to a can of baked beans. She's candid about her own sexual urges too – and takes ill-concealed delight in opportunities for vengeance. All of this is a great deal of fun.

But of course there's a purpose here beyond entertainment. The first objective is simply to tell Margaret's story, which is more akin to a Shakespearean tragedy than a history play; she lived in a time of conflict, had supporters and sources of power, yet proved herself unerringly able to pick the losing side. I'd have liked to feel a little more of the pain in English's performance, as the tale she's telling is certainly a poignant one.

English also sets out to skewer the propagandist liberties Shakespeare takes with Margaret's character. At intervals, the queen pauses to deliver a Bardic monologue – one drawn from each of the four pays in which she appears. The performances change sharply as Shakespeare's view of her evolves, from an air-headed simpering teenager to an embittered razor-tongued witch. And after each monologue comes a hilarious deconstruction, pointing out the many obvious ways in which the picture Shakespeare paints really makes no sense at all.

But the real theme – the one which underpins all the others – is the male-dominated society Margaret inhabits, and the ease with which we can recognise parallels to events of the modern day. This point comes through most powerfully in the summing-up at the end, and perhaps that moment could be even more impactful if earlier scenes laid the message on with a slightly smaller trowel. But this, it’s clear, is the reason why Margaret's story is so worth telling; why it's important to expose how our greatest playwright demeaned her, a woman who knocked on the doors of power.

English's dexterous monologue shows us that the forces which crushed Margaret have obvious analogues, in our response to powerful women today. It's a genuinely eye-opening production – a testament to theatre's ability to take facts we know intellectually, and set them in a context we can truly understand. So I recommend She Wolf for its informative storytelling, its insightful commentary… but also, unashamedly, because it's an enjoyable hour of sharp-witted fun.