One night, late in the summer of 1940, Tommy Sneum left his bed and slipped outside. He was on Fanø, the small island off the southwest coast of Denmark in the North Sea where he’d grown up. Curious to get a better look at the German defense installation nearby, he crept over the island’s sandy dunes and made his way through its small, stunted pines.

Suddenly he heard the drone of a plane. As the sound grew louder, Tommy could see the outline of a strange, rectangular piece of machinery on the other side of the installation fence. The mysterious machine began to swivel, then a searchlight switched on. That’s when Tommy spotted a silver plane overhead. The beam hit the plane precisely.

(Preceding image) A Spitfire I, flown by the British RAF.

Tommy could guess what it meant. He’d made a point to become friendly with some German officers, sometimes having beers with them at a local restaurant. These attempts to act as an undercover agent didn’t go over well with his old friends, who suspected him of being pro-German.

But Tommy’s efforts had paid off—big-time. One night, when he’d casually asked an officer if the Germans were afraid of the British bombing the Fanø installation, the man had let something slip. “ ‘They’d never reach us…. We’d be able to see them coming from far away…. We’ve got special technology.’ ”

Special technology. What might that be? Tommy was determined to find out. Now he was seeing it in action for the first time, and it “ ‘made me certain we were dealing with some kind of early-warning system. I was convinced that they now had the capability to plot the position of a ship or plane using radio waves.’ ”

Tommy was sure of something else too: If the Germans had a new early-warning system in place, it could spell disaster for British pilots. While he had no way of knowing whether Great Britain was aware of Germany’s new invention, which he learned later was called Freya radar, he wasn’t about to leave anything to chance. Here was something meaningful he could do on his own: Warn the British. It might also be a way to get into the war as a pilot. If he could escape Denmark and get to Great Britain, he might be allowed to join the British Royal Air Force.

Tommy wanted to be the one to deliver the information. He decided to try to get to the neutral country of Sweden, where the British had an embassy. He would then tell the British what he’d learned and offer himself up as a volunteer pilot. So in February 1941, posing as a Danish businessman, Tommy made it to the British legation in Stockholm, where he met with Captain Henry Denham, a naval attaché. Denham listened to Tommy’s report, although he didn’t seem as impressed as Tommy had hoped. Instead, he wanted Tommy to return to Denmark to get more evidence, saying, “ ‘We need to understand exactly how these things work. Get as much technical detail as we can.’

“ ‘I don’t see what more I could do,’ replied Sneum.

“ ‘You could take photographs,’ suggested Denham.”

Photographs? Tommy was skeptical. He couldn’t imagine just strolling up to the restricted military installation like a tourist with a camera slung over his shoulder.

“ ‘You could use a little Leica,’ continued Denham calmly. ‘Nothing too conspicuous. And if that works out, you could use a Movikon camera. They take moving pictures.’ ”

Tommy agreed to try. In March 1941, equipped with two cameras, untrained and untested, he became an unofficial spy for Great Britain. His mission: Get pictures and details on the new Freya radar machinery at a top secret installation.

(Preceding image) Tommy Sneum.

Tommy’s first break came when he boarded the ferry from the town of Esbjerg over to Fanø. As the ferry was about to set off, Tommy noticed that the engine had paused so that a last piece of equipment could be lowered by a crane onto the deck. Instantly alert, Tommy casually positioned himself for a closer look at what appeared to be some sort of control cabin. Could it have something to do with the German military installation on Fanø?

Tommy shot a quick glance around. No one was paying attention to him. “ ‘I couldn’t believe it. This was too good to be true, and I wasn’t about to miss my chance.’ ”

The door of the cabin had swung open as it was being lowered to the deck. Standing as close as he dared, Tommy grabbed his camera and snapped a few pictures from different angles. “ ‘It was one of the most dangerous moments but also one of the most satisfying.’ ”

Once on Fanø, Tommy began making plans to get shots of the Freya equipment. Realizing that he’d need to get as close as possible to the installation in daylight, he decided to pose as a hunter. Along with his camera, Tommy took a gun and even bagged some rabbits on the heath to make his story believable if he was stopped. Then he began to scout the installation, watching the guards closely as they patrolled the fences.

He needed to choose his moment carefully. Tommy knew that if he was caught, he’d likely be arrested, tortured, and maybe even executed by the Nazis. Once he had the guards’ routine timing down, he figured he had about one minute of safety when he could stand out in the open to snap pictures. He took as many pictures of the towers as he dared, then darted back under cover.

Tommy also wanted to show the radar in action. That meant using the primitive movie camera the Movikon, which was larger than the tiny Leica and would be a lot harder to carry inconspicuously. He would take the risk. Tommy asked a local friend named Peter, whom he knew was sympathetic to the cause, to help out. This time they would take bicycles. Peter would stand guard while Tommy shot the footage.

Tommy planned to wait until a plane came into view so he could capture the warning system in action. As the two rode their bicycles close to the trees near the installation, Tommy noticed that the sensors had started to rotate as the radar located an aircraft. Quickly he pulled out the camera from under his jacket and began filming.

Nearby, Peter hissed a frantic warning. “ ‘There’s somebody coming.’ ” Peter sped off on his bike, while Tommy tucked the camera under his jacket.

Tommy thought fast. He somehow had to create a diversion—a believable diversion—and he had to do it right then and there. The solution he came up with might seem comical, but it was all he could think of at the moment.

“ ‘I crouched down in the tall grass. In that squatting position, my knees were sticking out. That helped to hide the bulge created by the movie camera under my jacket. At the same time I pulled down my trousers and pants. The German officer came up with his rifle pointed at me. This was one of the most dangerous moments of my entire war. If he made me get up he would see the bulge of the camera and soon know I was a spy.’ ”

The soldier asked what he was doing, and Tommy replied crudely in German, pretending to be annoyed at his privacy being disturbed! The ploy worked. To Tommy’s relief, the man was so embarrassed he walked off without asking any more questions. As soon as he’d gone, Tommy jumped up, pulled up his pants, hopped on his bicycle, and was off. Tommy had been lucky—he knew he wouldn’t have been able to pull off this trick with a more experienced guard.

Although Tommy had escaped, the shots he’d managed to take were too far away to show details of the new radar technology. He’d have to try again.

Three days later Tommy made his next move. This time he would go alone. After scouting the area further he’d come up with a new plan. He would station himself at the foot of a water tower close to the installation. Trees grew close to it on one side. If he used those as cover he was fairly sure he could get to the right spot without being seen. There would be guards posted right over him, he knew, but that was simply a risk he’d have to take.

“ ‘Their blind spot was at the foot of the water tower itself…. When you are up in the tower, you are not going to be looking directly below you for the enemy, in your own area. You are going to be looking out to sea for ships or aircraft.’ ”

Tommy set out under the cover of darkness up the wooded hill to the water tower. Once there, he was so close he could hear the voices of the guards above, chatting in German. Tommy waited for dawn, then for something to happen. At last a plane approached.

Tommy clicked on his camera, capturing the large, revolving structure as it followed the path of the aircraft. This time if he got caught, there would be no fooling the Nazis. When he noticed the guards above moving to look in a different direction, he decided that was enough. Slipping the camera under his jacket, he bolted back under the cover of trees and took off.

Part of him waited for the order to halt. “ ‘I had already decided to keep running if that happened, even if it meant I risked being shot in the back…. To be captured would have meant torture.’ ” As he made his way through the woods, all he could hear was the sound of his own breath. “ ‘I wanted to shout with joy, but I couldn’t.’ ”

Tommy Sneum had done it: He had captured Freya radar in action. What he had found might help save lives, not just in Denmark but also in other parts of Europe. If the Germans were using this equipment here, it might well be part of their defense systems elsewhere. While it might be possible to sneak into Sweden, Tommy thought the danger of carrying the bulky film reels was too high. He’d risked his life for these shots; he needed to get his precious reels into the right hands.

Tommy made up his mind. He would deliver the films to London himself. And so he began planning one of the most daring feats of World War II.