Last night's viewing: Restless, BBC1 Racing Legends, BBC2 World’s Most Dangerous Road, BBC2

“Is Sally your real Mummy?” asks young Jochen, as he’s being taken by his mother to visit Granny in the country. “It’s just she’s so strange.”

Ruth, Jochen’s mother, seems a little taken aback by this judgement at the beginning of Restless, William Boyd’s adaptation of his own 2006 spy thriller. But it isn’t long before Ruth is thinking something similar. “Did anybody follow you?” asks Sally when they arrive, “There are people in the woods. People who are watching me.” Oh dear, thinks Ruth, it’s started. This isn’t the onset of dementia though, because there really are shadowy figures in the tree-line and Sally turns out to have the kind of past that can dog you into old age. Soon, Ruth has discovered that Sally isn’t Sally at all, but Eva Delectorskaya, a former British spy.

It’s the kind of thing that children often wishfully fantasise about their parents but which they almost always discount, because dull familiarity smothers the daydream. But that’s one theme of Boyd’s story. “No one knows even half the truth about anyone else... even when they’re very close,” Sally tells Ruth a little later, a lesson we suspect she has learnt the hard way, as a result of her own earlier betrayals and astonishments. Given that Sally is played by Charlotte Rampling, you might have thought that Ruth would have had her suspicions anyway. Rampling only has to appear on screen to suggest a concealed back story of some kind. But then children always assume that their parents have only a kind of depleted half-life compared to their own.

Boyd’s deft screenplay, like the novel, cuts between the memoir that Ruth is given to explain her mother’s past history, and the present day, where she finds herself recruited as a kind of double agent too, helping to track down her mother’s former lover. Hers is a rapid and occasionally blackly comic education in her mother’s hidden talents, nicely summed up by the scene in which Ruth unexpectedly spots her walking down a street in Cambridge and tracks Granny to a gun shop, where she finds her buying a pump-action shotgun and specifying her taste in cartridges with an unnerving assurance.

For the moment, we’re more in the past than the present, with Haley Atwell playing the young Eva as an initially reluctant recruit who discovers (like similar characters in David Hare’s Plenty and Sebastian Faulks’s Charlotte Gray) that wartime and danger add a certain spice to life. In the young Eva’s case, the spice includes Lucas Romer, a senior intelligence officer who interprets his duties as her “handler” with a satisfying degree of erotic licence. When Eva travels with him to America, to help lever the United States into war by means of black propaganda, she discovers that she’s expected to serve as a honeytrap and that Romer’s own allegiances may be complicated. In another fine moment of narrative-by-casting we discover, in the final frame, that the elderly Romer is played by Michael Gambon, as good as a confirmation that we don’t yet know half the truth about him.

Two treats for petrolheads last night, the first in the shape of Racing Legends, in which Patrick Stewart got to meet his boyhood hero Stirling Moss and drive around in some of the cars that made his name. Genuine passion is a high-octane fuel for a television programme, and there was no question that that was what Stewart had in the tank, judging from the tremor of excitement on his face as he climbed into a Mercedes Gullwing to drive part of the route of the Mille Miglia. Treat two was World’s Most Dangerous Roads, in which Angus Deayton and Mariella Frostrup tackled 300 kilometres of Madagascan quagmire, enlivened by the occasional broken bridge and derelict ferry. If you are facing a long haul back along a motorway today it should have put the ordeal into perspective.

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