Hansard is the debut play by actor Simon Woods, who enjoys a deep knowledge of his subject. The characters are a middle-aged couple, the Heskeths, who occupy
‘a country house in Oxfordshire. Georgian. Good bones. Not large’. The year is 1988 and Robin is a busy Tory MP whose wife Diana has realised that she loathes the Conservative party and all its doings. ‘They talk a good game,’ she says, ‘but they’re unbelievably dangerous.’ As a lifelong leftie, she has even started begging strangers to vote against her husband, whose policies ‘inflict damage on the most vulnerable in society’. She also suspects him of philandering and has taken to appearing unannounced at his London flat.

Robin shares his wife’s talent for invective. To start with his insults are affectionate. ‘They don’t think you’re left-wing, darling, they think you’re highly strung.’ Later he gets unpleasant. He asks if her daily workload involves anything more than ‘moving the cushions around on the sofa’. And he dismisses her needy sexual advances as a symptom of Alzheimer’s. ‘First you left that courgette in the knife drawer, and now this.’ He blames her lustiness on drink. ‘Your allure smells like a marquee on the morning after a wedding.’

This is vicious stuff but the delivery is feather-light and charming. Perhaps the writer intended to portray Robin as a sadistic Tory ogre but Alex Jennings gives his cruel barbs an innocuous, even sophisticated playfulness. And Diana (Lindsay Duncan) seems oddly content to endure his put-downs and even to encourage them.

Those who recall the 1980s will recognise that the period dialogue is almost faultless. People of Robin’s age liked to call Princess Diana ‘Lady Di’ — a label coined by the tabloids when she first emerged as Prince Charles’s girlfriend. But no one in the 1980s said ‘back in the day’, which belongs to the present century. Occasionally the repartee is too finely crafted. Robin suggests that Diana bequeath her pickled liver to science. ‘Ginorously donated,’ he says, as if improvising this contrived pun. It may look fine on paper but it works less well on stage.

One question nagged me throughout this enjoyable exhibition of verbal pugilism. Why? Why has an intelligent and resourceful woman such as Diana chosen to perpetuate a sham marriage and to waste her life boozing in the Tory heartlands surrounded by people whose world outlook she detests. Might she not pick herself up, start afresh and stop moping?

The answer comes in the final ten minutes of the show as the story takes a very steep and sudden dive from a lightweight marital comedy to a harrowing family tragedy. The bond that keeps the warring Heskeths together is explained, and we learn the truth about Robin’s philandering. I wasn’t convinced that the final scenes were psychologically consistent with the prickly wordplay of the earlier sections. The actors themselves must wonder why Robin and Diana are so relentlessly nasty to each other when they have so much shared history to cherish. But this illogicality will strike only those who see the show more than once. This is an excellent bet for a transfer. It’s funny, it’s short and, above all, it has just two actors. So, nice and cheap.

A Very Expensive Poison, adapted by Lucy Prebble from Luke Harding’s book, begins with a Chris Grayling joke. ‘He’s a colossal tit,’ says a lawyer advising Marina Litvinenko about the inquiry into the assassination of her husband, Alexander, in 2006. The play then cuts back to the fateful night when the Russian-born ex-pat was rushed to A&E with stomach cramps. Rather surprisingly, we’re shown a London hospital staffed almost exclusively by prim yuppies speaking in Home Counties accents. Where are the EU migrants who keep our sacred health service afloat?

We then flip back another ten years to Alexander’s life in Moscow when he was a middle-ranking detective in Putin’s secret service, the FSB. His bosses order him to commit a wet job (assassination), and his reluctance to comply puts him at odds with the Russian leader. He flees to London where two bungling assassins are sent to rub him out.

This sprawling, bubbly, good-humoured show uses a variety of effects — dancing, puppetry, karaoke, sketch-show comedy — to tell its story. At one point, three huge puppets representing Yeltsin, Brezhnev and Gorbachev enter the stage and try to squeeze on to a tiny sofa. Putin appears like a menacing nightclub boss and prowls the Old Vic making sardonic comments into a handheld microphone. These details may sound chaotic and self-indulgent but the designs are high quality and the effects are always stimulating.

Lucy Prebble’s breakthrough hit, Enron, was marred by unpleasant characters and a preachy attitude to capitalism. Here she explores a complicated and rather arcane slice of history with great visual panache.