This version of Buchan's tale starred Robert Powell as Richard Hannay, Karen Dotrice as Alex, John Mills as Colonel Scudder, and a host of other well-known British actors in smaller parts.

The early events and overall feel of the film bear much resemblance to Buchan's original story, albeit with a few changes such as the re-casting of Scudder as a more immediately sympathetic character and the introduction of a love interest.

It also introduces a different meaning for the "thirty-nine steps", although unlike its filmed predecessors it returns to Buchan's original notion of being an actual staircase.

It is known for the Big Ben sequence near the end, inspired by the film My Learned Friend (1943) starring Will Hay, although this is its most fundamental deviation from Buchan's original story, which reaches its culmination in a coastal location in Kent.

He turns to Richard Hannay, a mining engineer who is visiting Great Britain for a short time before returning to the Union of South Africa, who happens to be staying in a flat in the same building.

In the morning, Hannay leaves to purchase a train ticket to his family hometown, the village of Strathallan north in Scotland, while Scudder remains at work on his notes in the flat.

When the Prussian agents attempt to enter the flat, Scudder flees down the fire escape but he is spotted posting a package containing his secret notebook in a pillar box.

Hannay flees to Scotland on a northbound train, but he is forced to make a daredevil escape jumping on a bridge when the police board the railway cars.

On the Scottish moors Hannay, claiming to be on the run as part of a wager, meets Alex Mackenzie and her fiance, David Hamilton.

On the run again, Hannay has to pose as a Liberal Party political orator and ad lib a speech at an election husting campaign stop.

The agents intend to murder the visiting Royal Greek Prime Minister by planting a bomb in the Palace of Westminster, while the British Parliament is meeting thus also causing a criminal terrorist incident, leading to unrest in the always unstable Balkans peninsula (southeastern Europe) and precipitate an international crisis, possibly striking a world war.

To give the police more time, Hannay breaks the glass of the outside clock-face, climbs out onto the face of the clock, almost 100 meters above ground and physically stops the minute hand as it moves towards the figure IX (11:00 pm).

Lomas recognises a Thames River Police uniform and at the docks Hannay and other officers capture Appleton, who had also stolen secret details of the deployment of all Royal Navy warships.

Sir Edmund Appleton is convicted of treason and Richard Hannay is declared a hero for helping Britain gain valuable time to prepare defences for a future "Great War'.

[8] The idea of Hannay dangling from the hands of Big Ben came in part from a stunt performed by Harold Lloyd in the silent comedy classic Safety Last (1923).

The privately owned Severn Valley Railway loaned the film a steam engine, together with rolling stock and a section of track, for shooting.

Rank's head of Leisure, Ed Chilton, felt this was incnsistent with the rest of the film so a shot was added to give the indication of a happy ending.