He was also a British Special Operations Executive intelligence officer for Section D and an espionage agent, both in pre-war Belgrade and during World War II in Yugoslavia.

He reported on a wedding talking place in Belgrade between Prince Nicholas Wladimirovitch Orloff, (who divorced Princess Nadejda Petrovna of Russia the previous week), and an American actress, successful only in Germany, Mary R. Shuck went by the stage name of Marina Marshall.

When he eventually emigrated to the United States he was suspected by U.S. agencies as being Lord Haw-Haw, as he was responsible for broadcasting Nazi Propaganda in English over the airwaves before the war.

However rivalries and confusion and lack of continued interest by the British Foreign Office in this region of Europe did little to help matters of diplomacy in Atherton's adoptive home.

His mission was to remain close to Yugoslav leaders until the armistice, evade capture by Axis-forces, and exit the country by any means and reach British troops in Greece.

[22] In order to evacuate from Belgrade, Atherton acquired a car (a small blue Opel coach) and drove first to Banja Koviljača and then onto Užice and to Zvornik following the retreating Yugoslav government.

[23] Atherton would later write that he was in the presence of the new Prime Minister, General Dušan Simović,[24] as he witnessed "first hand", the collapse of the government of national unity, from a small town in Bosnia, within less than 10 days.

Atherton, realizing the severity of his own situation, and of his American companions, continued overland onto Cetinje, and then onto the coastal port of Budva in Montenegro as an Italian occupation force began entering the ancient walled town.

Shortly prior to this date, in Budva, Atherton seized a small sardine boat, in exchange of his Opel car, and remained hidden in the port until it was safe to leave.

With no charts or a compass; only 12 gallons of fuel, some road maps, and a gunny sack of bread, Atherton set off with his 3 companions on a dangerous voyage through Albanian coastal waters, a region subject to invasion and now in control of the Italian forces, in an attempt to safely reach the Greek island of Corfu.

[27] His traveling companion, St John was the only experienced sailor, who later recounted the tale of treacherous weather conditions and the groups imminent danger when an Italian Navy vessel accompanying troop movement ships spotted their small open boat, and subsequently trained their guns on them in proximity to Durrës.

[21] Eventually the local authorities permitted them to sail south, where they were subsequently machine gunned by Italian fighter planes, and their vessel quickly sank.

Atherton and his companions were rescued by a small Greek fishing trawler, which also fell victim to an air attack; this time by 5 Stukageschwader Stuka dive bombers, and suffered fatalities.

They knew they needed to join a British evacuation since the Axis forces were advancing swiftly in the Balkans.However German planes machine gunned the passenger train, wounding two of Atherton's American companions.

However, due to the deteriorated relations between this Serb general, the self-appointed leader of the Chetnik Detachments of the Yugoslav Army, and the British liaison officer, Duane "Bill" Hudson, stationed temporarily outside of Mihailović's headquarters and engaging with partisans as part of Operation Bullseye whilst under radio silence, the SOE, not having heard from Hudson, decided at the end of 1941 to send a second mission to open up channels of communication with partisans, as well as maintain a connection with the Chetniks, and keep to script.

[39] Operation Hydra (Yugoslavia) was a failed attempt by the British during World War II to develop contact with the Yugoslav Partisans, the leading Communist-led Anti-fascist resistance group led by Josip Broz Tito, in Montenegro in February 1942.

Special Operations Executive agents, including a former junior officer of the Royal Yugoslav Air Force were to be put ashore at Perazića Do, just north of Petrovac, Budva, Montenegro.

On 4 February 1942, Atherton and two other field agents, Lieutenant Radoje Nedeljković of the Yugoslav Royal Air Force and Sergeant Patrick O'Donovan, an Irish born radio operator, went ashore just north of Petrovac from the British submarine HMS Thorn.

[44] Ivan Milutinović wanted to kill the British agents when they arrived to the Partisan HQ on 12 February 1942, because he thought they were acting on behalf of the Yugoslav government-in-exile, but he did not do it because he received a letter from Tito instructing them to bring Atherton and his team to the headquarter of supreme command near Foča.

[49][50] In Foča in March 1942 he also met Vladimir Velebit who later confirmed that for Atherton Partisans were only "a bypass or way station" en route to Draža Mihailović, just as they had experienced with Hudson the previous year.

[44] Based on the discussions during the session of the Central Communist Committee held on 4 April 1942, Tito issued instructions to find and isolate all British missions.

Ivan Milutinović had numerous exhausting polemics with Atherton in futile attempts to convince him to change his positive view about Chetnik leader Draža Mihailović.

[59] When they arrived at Partisans headquarter near Foča, Atherton also met Vladimir Dedijer[12] who showed him some agreement about alleged Chetniks cooperation with Milan Nedić.

[62] The Yugoslav post-war sources emphasize that Partisans managed to convince Atherton to change his pro-Chetnik and anticommunist view at the extent that he began arguing with General Petar Nedeljković, according to the letter sent to Pijade by Tito on 11 April 1942.

[66] Latas explained that Atherton had some disagreements with General Nedeljković and on 22 April 1942, continued on foot, headed towards German-occupied Serbia to seek Mihailović, accompanied only by O'Donovan.

[68] Atherton's friend and former assistant editor at the South Slav Herald in Belgrade, Alexander Simić-Stevens took part in Operation Fungus which departed Derna, Libya in April 1943.

[71] Based on initial testimonies that he was killed by Partisans, The New York Times[72] published an article blaming them for his death, which was denied by a letter written by Tito (the future Yugoslav Head of State) himself.

[77]According to the late Croatian military historian Jozo Tomašević, the investigation led by Hudson and William Bailey concluded that Atherton was murdered and robbed by local Chetnik commander Spasoje Dakić in the village of Tatarovina, in modern-day Northern Montenegro.

The British government response delivered by the Under-Secretary of State for War, Arthur Henderson MP was that the circumstances in which he died 3 years prior were still unclear.

[85] Later during the trial under cross examination Mihailović advised that he had conducted a personal inquiry in 1942 into the likely murder of Atherton, who admitted that he had probably been executed on the orders of one of his subordinate generals.