Some 40 years ago, before MI6 chiefs could be embarrassed by their wives putting holiday snaps on Facebook — when, indeed, there was no Facebook and MI6 itself was a state secret — John le Carré was drawing on his own service in it to create some of Britain’s most successful postwar novels, and the quiet, cunning, meticulous agent George Smiley.

Television, cinema and radio have each previously adapted one or more of the Smiley books, but Radio 4 has now gone a step further and is dramatising all eight of them. The sequence began in May with the first one, Call for the Dead, and will end next April with the last, The Secret Pilgrim. The Spy Who Came in from the Cold is on the air now as a three-part classic serial, and the middle episode goes out this afternoon: FM only because of cricket on longwave, but, like all the Sunday-afternoon serials, repeated on Saturdays and also available on digital.

These dramas (seven espionage stories and one whodunit) offer much that is enjoyable: subtle and unobtrusive sound effects, from scratching pens to assemblage of whisky and soda; a sense of cold war shadows and shifting moral sands; the evocation of a vanished Britain; and a taut, complex but intelligible narrative.

There is also a problem, though, and that is the star — Simon Russell Beale, who plays Smiley. He is a very clever man: a Cambridge scholar, a musician, a BBC4 presenter and a versatile stage actor of international renown. The problem is that he never sounds as if he is of the period. The 1950s and 1960s voice, clipped and precisely enunciated, is absent when he speaks. His words, and syllables, tend to run into one another, and he has even pronounced “recognised” as “reconnised”. His voice has strong sinews, but it is simply not the voice of the period.

He is not alone in this: Brian Cox, who today continues in the central role of the undercover operative Alec Leamas, sounds equally contemporary. So does Ruth Gemmell, who plays the Jewish Communist Liz and becomes his lover, and who has an extraordinarily sexy voice. It is mainly the less famous players, such as John Rowe (Control at the MI6 base at the “Circus”) and Liza Sadovy (the tense librarian Miss Crail), who are both in the present production, and Marcia Warren (the Christian magazine editor Miss Brimley in A Murder of Quality), who most effectively, and instantly, conjure up the era of Bakelite telephones and black-and-white television. The odd thing is that the producer of these dramatisations, Patrick Rayner, has evidently not insisted that all members of the cast try to speak with the same perfect nuance: perhaps he was overawed by his stars.

Russell Beale is the sixth actor to play Smiley in broadcast adaptations of the novels, following George Cole (Radio 4, 1978), Alec Guinness (BBC2, 1979 and 1982), Peter Vaughan (Radio 4, 1983), Bernard Hepton (Radio 4, 1988 and 1990) and Denholm Elliott (Thames TV, 1991). In addition, Rupert Davies played him on film.

Guinness made by far the most impact, though I do not think anyone ever captured Smiley’s precision, resolution and emotional detachment as well as Hepton. But what does le Carré himself have to say about the Smileys of the airwaves? Alas, he is “away writing and cannot be disturbed”, says his agent. Saving his verdicts for his memoirs, perhaps.

paul.donovan@sunday-times.co.uk

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