Olivia Williams is a London girl, which is fitting for someone who we'll next see playing a mayoral candidate in the TV play City Hall, written by her husband, the actor and playwright Rhashan Stone. Growing up in Camden, she used to pass through Marylebone, where she now lives with Stone and their two daughters, on her way to Saturday-morning ballet class; she originally thought this flat would be her "bachelorette pad… my happy acceptance of permanent singledom".
Now it is filled with the evidence of busy family life, but this sitting room, with its pristine white carpet, remains an oasis of serenity. A clutch of disembodied heads adorns the mantelpiece. The largest is, somewhat unexpectedly, a polystyrene wig block, the middle one a plaster-of-Paris cast made for a special effect in a film, and the smallest a model of a baby's head made by Williams's grandmother. Either side of the mirror are two pictures that Williams bought at "the beginning of my earning power", having been educated, she explains, in the knack of acquiring beautiful objects by her lawyer father, who also bought her the 18th-century Iznik plate on the right-hand side of the mantelpiece.
In the hearth stands evidence of Williams's acting pedigree: a photo of her great-great-grandfather playing a butler alongside Marie Tempest in a play that might or might not be called You Never Can Tell. The other photographs are of Williams's daughters.
Elsewhere are the fruits of travel: scarves that she brought back from youthful adventures in northwest Afghanistan (clearly now hiding the telly), and an intricate mask that her husband came across on a recent work trip to South Africa.
Mementoes of Williams's own prolific and wide-ranging career are confined to a poster for the film Rushmore, propped up against the wall, and a copy of Robert Harris's The Ghost – she took the lead female role in Roman Polanski's adaptation, The Ghost Writer. It's hardly surprising – she comes across as an actor very unlikely to be engaged in the business of flamboyant self-display.
City Hall is on Thursday 3 May at 9pm on Sky Arts 1. Go to sky.com/arts
