The film begins with captured Second World War film footage of the rescue from Italy of Mussolini by German paratroopers. Inspired by the rescue of Hitler's ally Benito Mussolini by Otto Skorzeny, a similar idea is considered by Hitler, with the support of Himmler (Donald Pleasence). Admiral Canaris (Anthony Quayle), head of the Abwehr (German military intelligence), is ordered to make a feasibility study of the seemingly impossible task of capturing the British Prime Minister Winston Churchill and bringing him to Germany.
Canaris considers the idea a joke, but realises that although Hitler will soon forget the matter, Himmler will not. Fearing Himmler may try to discredit him, Canaris orders one of his officers, Oberst Radl (Robert Duvall) to undertake the study, despite feeling that it is a waste of time.
An Unteroffizier on Radl's staff, Karl, finds that one of their spies, code named Starling, has provided tantalising intelligence: Winston Churchill is to visit an airfield near the (fictitious) village of Studley Constable in Norfolk, where Joanna Grey (Jean Marsh), a German sleeper agent lives. Radl comes up with a scheme that could work, called 'Eagle', where the kidnapping will proceed with German troops leading the action. He also is convinced that synchronicity is behind it all, where actions and conditions merge at the proper moment, at the proper time.
Himmler summons Radl and unofficially tells him to proceed, without notifying Canaris but with Hitler's knowledge, providing Radl with an 'authorising' letter signed by Hitler himself. Radl recruits Liam Devlin (Donald Sutherland), a member of the IRA lecturing at a Berlin university, to the mission.
Radl looks for a suitable officer to lead the mission and chances upon the highly decorated and experienced, but conflicted and anti-Nazi, Fallschirmjäger officer Oberst Kurt Steiner (Michael Caine). While returning from the Eastern Front, Steiner intervened when SS soldiers rounded up Jews at a railway station in Poland, and attempted to save the life of a teenage girl who was shot while trying to escape. For this, he was court-martialled, along with a platoon of his men. Rather than face the firing squad, the men were allowed to transfer to a penal unit on the Channel Island of Alderney, where they made high risk attacks with Neger Manned Torpedoes against English Channel convoys.
Radl travels to Alderney and, with the help of Devlin, recruits Steiner and his surviving men. The team will parachute into England from a captured C-47 with Allied markings. The commandos outfit themselves as Polish paratroopers, as few of them speak English. The plan is to infiltrate Studley Constable, complete their mission, rendezvous with an E-boat on the nearby coast and escape. The paratroopers land and the operation proceeds.
Radl visits Himmler to announce that "The eagle has landed", but then Himmler destroys the authorising document he'd given Radl, suggesting that Himmler invented Hitler's approval.
As the Germans take up positions in the town, the plan is foiled when a paratrooper rescues a local girl from certain death by a water wheel. He instead is killed in the process and his German uniform (worn under the Polish uniforms at the prior insistence of Steiner) is revealed to the onlooking villagers. The locals are rounded up into the village church, but Pamela Vereker (Judy Geeson), the sister of the village priest Father Vereker (John Standing), escapes to alert a unit of the United States Army Rangers stationed nearby. Inexperienced, glory-seeking Colonel Pitts (Larry Hagman) tries to foil the German plan almost single-handed but is killed by treasonous Nazi sympathizer Joanna Grey in her house, while his poorly-planned assault on the church fails with heavy casualties. Pitt's young deputy, Captain Clark (Treat Williams) then organises a second, successful attack.
Steiner's men sacrifice themselves to delay the Americans while Devlin, Steiner and his wounded second-in-command Neustadt (Sven-Bertil Taube) escape, with the aid of local girl Molly Prior (Jenny Agutter) who was romantically involved with Devlin. Instead of boarding the escape boat, Steiner vows to make one last attempt at Churchill.
Receiving news by radio of the apparent failure of the operation, Radl orders his assistant Karl to leave Alderney immediately and return home to Germany, in order to avoid the fate Radl knows is forthcoming. Radl is then arrested and summarily executed by firing squad, under the pretext that he "exceeded his orders to the point of treason". In this way Himmler distances himself from the failed mission.
Steiner does manage to infiltrate the country house and apparently succeeds in killing Churchill before being shot and killed himself. Captain Clark, on scene, is stunned by Churchill's death, but is then informed by security personnel that "Churchill" was actually George Fowler, an actor and impersonator – the real Prime Minister is at the Tehran Conference. Clark and a superior officer are also advised that, "No one will ever know about this. This never happened. It did not occur."
Devlin, evading capture, leaves a love letter for Molly, and disappears to live in obscurity.
Film rights were bought by Jack Wiener for Paramount in 1974.
Caine was originally offered the part of Devlin but did not want to play a member of the IRA, so asked if he could have the role of Steiner. Richard Harris was in line to play Devlin but ongoing comments he had made in support of the IRA drew threats to the film's producers, so he was forced to withdraw and Donald Sutherland was given the role. Tom Mankiewicz thought the script was the best he had ever written "but John Sturges, for some reason, had given up" and did a poor job. He said editor Anne V. Coates was the one who saved the movie and made it watchable.
Michael Caine had initially been excited at the prospect of working with Sturges. During shooting, Sturges told Caine that he only worked to earn enough money to go fishing. Caine wrote later in his autobiography: "The moment the picture finished he took the money and went. [Producer] Jack Wiener later told me [Sturges] never came back for the editing nor for any of the other good post-production sessions that are where a director does some of his most important work. The picture wasn't bad, but I still get angry when I think of what it could have been with the right director. We had committed the old European sin of being impressed by someone just because he came from Hollywood."
Cornwall was used to represent the Channel Islands, and Berkshire for East Anglia. The majority of the film, set in the fictional village of Studley Constable, was filmed at Mapledurham on the A329 in Oxfordshire and features the village church, Mapledurham Watermill and Mapledurham House, which represented the manor house where Winston Churchill was taken. A fake waterwheel was added to the 15th century structure for the film. Mock buildings such as shops and a pub were constructed on site in Mapledurham while interiors were filmed at Twickenham Studios. The "Landsvoort Airfield" scenes were filmed at RAF St Mawgan, five miles from Newquay.
The sequence set in Alderney was filmed in Charlestown, near St Austell in Cornwall. Some of the filming took place at Rock in Cornwall. The railway station sequence where Steiner and his men make their first appearance was filmed in Rovaniemi, Finland. The parachuting scenes were carried out by members of the REME (Royal Electrical and Mechanical Engineers) Parachute Display Team. The exit shots were filmed from a DC-3 at Dunkeswell Airfield in Devon. The landings onto the beach were filmed on Holkham Beach in Norfolk.
There is a scene where Radl and Karl look at an Ordnance Survey map with a magnifying glass at an area just south east of present-day Wells-next-the-Sea. This seems to suggest that the filmmakers wanted 'Studley Constable' to be located between Warham, Wighton and Binham. This is only a few miles from Holkham where the parachute drop was actually filmed. Reading of the book suggests the fictional village may have actually been based on nearby Cley next the Sea.
The original theatrical running time for the film was 135 minutes in Europe, while 12 minutes were cut by the distributors before its US release.
US and UK VHS cassettes had the 123 minute US cut. All DVDs and Blu-rays currently available worldwide now feature the original UK theatrical cut, which in DVD region 2 and 4 countries runs 130 minutes at 25fps (PAL speed). There are two exceptions:The first US (NTSC) DVD, from Artisan Entertainment, had some missing scenes reinstated for a runtime of 131 minutes. It has been superseded by a Shout! Factory Blu-ray/DVD dual format set, containing the UK theatrical cut and various extras.
In 2004 Carlton Visual Entertainment in the UK released a two-disc Special Edition PAL DVD version which contains various extras and two versions of the film: the UK theatrical version and a newly-restored, extended 145 minute version, equating to 151 minutes at 24fps (film speed). Despite the packaging claiming otherwise, both versions have a 2.0 stereo surround soundtrack.
The extended version contains a number of scenes that were deleted even before the European cinema release:Alternative opening: originally the film was intended to start with Heinrich Himmler (Donald Pleasence) arriving at Schloss Hohenschwangau for a conference with Hitler, Canaris, Bormann and Goebbels. It precedes the scenes under the opening credits which are a long aerial shot of a staff car leaving the castle in question. The deleted scene explains why Schloss Hohenschwangau appears in the credits but does not appear in the film.
Extended scene when Radl arrives at Abwehr headquarters; he discusses his health with a German Army doctor (played by Ferdy Mayne).
Scene at a Berlin University where Liam Devlin is a lecturer.
Scene in Landsvoort where Steiner and von Neustadt discuss the mission and its merits and consequences.
Devlin's arrival at Studley Constable is now extended where he and Joanna Grey discuss their part in the mission.
Devlin drives his motorbike through the centre of the village and on to the cottage, where he inspects the barn before returning to the village.
Scene where Devlin reads poetry to Molly Prior.
Extended scene in which Molly interrupts Devlin shortly after he receives the army vehicles.
Scene on the boat at the end that shows the fate of von Neustadt. This scene is also visible in the Special Edition DVD stills gallery.
The film was a success, with Lew Grade saying "it made quite a lot of money". ITC made two more films with the same production team, Escape to Athena and Green Ice.
In his review for The New York Times, Vincent Canby called the film "a good old-fashioned adventure movie that is so stuffed with robust incidents and characters that you can relax and enjoy it without worrying whether it actually happened or even whether it's plausible." Canby singled out the writing and directing for praise:
Tom Mankiewicz's screenplay, based on a novel by Jack Higgins, is straightforward and efficient and even intentionally funny from time to time. Mr. Sturges ... obtains first-rate performances building the tension until the film's climactic sequence, which, as you might suspect, concludes with a plot twist. ... With so many failed suspense melodramas turning up these days, it's refreshing to see one made by people who know what they're about.