Coming to the assistance of a nanny who is almost killed during a bungled hit-and-run assassination attempt, Richard Hannay is surprised to find that there is no baby in her pram.

Afterwards, she goes back to Hannay's flat with him, where she reveals that she is a spy working for British Intelligence following a group called "The Thirty-Nine Steps"; all they know about their elusive leader is that he is missing the tip of a finger.

The Thirty-Nine Steps are in possession of a set of top-secret plans for "Boomerang", a British ballistic missile project that could tip the balance of power in Europe.

Fearing he will be accused of her murder, Hannay decides to continue her mission and catches an ex LNER Class A4 hauled train to Scotland from King's Cross railway station, having evaded the hitmen outside his flat by adopting a milkman disguise.

He then meets Percy Baker, a helpful ex-convict lorry driver who advises him to stop at "The Gallows", an inn owned by Nelly Lumsden, who was once imprisoned for practising the occult.

A burst tyre gives Hannay his chance to escape, but only having one hand to drive with, he crashes the car, forcing him to wander through the bleak Scottish Highlands handcuffed to Miss Fisher.

The finale is back in the Palace Music Hall where Hannay provokes Mr Memory into telling him where "The Thirty-Nine Steps" are, just as the police arrest him.

[3] As the Rank Organisation owned the rights to the Alfred Hitchcock's 1935 black-and-white adaptation, a number of the 1959 film's scenes are based on the earlier production, including the music hall opening, the escape on the Forth Bridge and the addition of a female love interest for Hannay.

[4] Andrew Spicer notes that "Critics detected a reassuring period feel to the visual style, with More as the pipe-smoking, sporting gentleman in a flat cap."

[citation needed] More had carved himself a niche as a leading man of 1950s British cinema, having appeared in heroic roles in films such as Reach for the Sky and A Night to Remember.

[12] The casting of Taina Elg was unpopular with contemporary critics, who felt her performance to be unconvincing, feeling that "her beauty is frozen by the uncertainties of ignorance, if not of neuroticism".

[6][14] In addition to the primary cast, the film features a number of small appearances by British actors who were to become well known from their later work, for instance Joan Hickson as a teacher and Brenda de Banzie as a psychic.

Many of the melodic themes throughout the film derive from pieces performed by the house orchestra during the early music-hall scene, particularly the Mr Memory motif.

[citation needed] Comparing it with Hitchcock's version A.H. Waiton writing in 1960 suggested: "the pace, as well as the execution is milder, more civilised and somehow less suspenseful than it seemed previously.

"[13] Reviewing it more recently for LoveFilm, Mark Walker opined: "As a thriller it's hardly in the same league as North by Northwest, but as a window on life in England and Scotland in the 1950s, this 39 Steps has much to recommend it.

[24] Sight and Sound wrote: Although Frank Harvey's script provides some innovations (the political meeting into which Hannay erupts has become a girls' school lecture introducing a St Trinians touch), it owes far more to the first screen version than to Buchan's novel.

Ralph Thomas, the director, intermittently tries for Hitchcock's particular blend of the sinister and the comic; and he pulls out one trick, when a pram blanket is drawn back to reveal not a baby but a pistol, entirely worthy of this tradition.