The hotels in Estoril and Lisbon were a hotbed of spies at the time. The Palacio was used by the Allies whereas the Germans used the Atlantico. The staff in each were more than willing to spy on the guests for a fee.
Ironically the Palacio Hotel was used in 1969 as a set for the Bond film ‘On her Majesty’s Secret Service’.
Operation Golden Eye had a profound effect on Fleming - it was the nearest he ever got to becoming a secret agent, and he would name his house on Jamaica ‘Goldeneye’ after it.
How, then, did it come about?
As France was falling in 1940, Fleming was sent by Godfrey to try and locate, and stick with, Admiral Francois Darlan - commander of the French Fleet.
Churchill was desperate to know his intentions regarding the fleet, should France fall. Darlan was a slippery customer and hard to stick to or get an answer from - this resulted in the Royal Navy having to sink part of the French Fleet at Oran, North Africa.
But some have suggested that Fleming himself saw little real action during the war, only a brief exposure from the deck of the destroyer HMS Fernie during the Dieppe landings.
It’s true that he was largely a desk-bound sailor, an ideas man.
Yet, during his mission to find Darlan, he became entangled in the retreat into southwestern France on roads choked with refugees and military units being bombed and strafed by the Luftwaffe.
At Bordeaux, Fleming got involved with the loading of ships in the Girande estuary, in one case making sure there was space on one of the evacuation ships for a large quantity of aircraft engines.
Many saw him at the time as a well-spoken RNVR (Royal Naval Volunteer Reserve) officer exuding a confident air amid the dockside chaos.
Surely, all this amounted to ‘seeing action’?
Returning to Britain, Fleming was sent straight off again to see the Naval Attaché in Madrid - Alan Hillgarth - to assess the effect the German victory might have in Spain.
Hillgarth had served in the Navy during the First World War and had lived in Spain for years.
Between them, they hatched Operation Golden Eye - a stay-behind scheme where sabotage teams would hinder any German move into the Iberian Peninsula.
He went onto Gibraltar and then to Tangier to assess the situation there. He was back in London by August 1940.
There, Golden Eye was subdivided into two plans: Operation Sprinkler, to assist the Spanish if they resisted a German invasion; and Operation Sconce, for if the Spanish cooperated with the Germans.
Both would mean Section H of the newly formed SOE (Special Operations Executive) deploying sabotage teams using Spanish guerrillas to hit transport links and fuel stores.
My book explores several schemes that were used to keep Spain neutral.
British Ambassador to Madrid, Sir Samuel Hoare, embarked on one venture with Hillgarth to bribe high-ranking Spanish Government officials and military officers into supporting Britain.
They were aided in this by Juan March, a wealthy Spanish businessman who had first been recruited by Colonel Charles Thoroton RM, who had run Naval Intelligence in the western Mediterranean during World War I.
March remained loyal to Britain during World War II and much of the Thoroton/March network was still intact by 1940 and was to prove a vital advantage to the British.
Largely unknown to the British, Adolf Hitler and Francisco Franco had met at Hendaye on the Franco-Spanish border in October; the Fuhrer expected his plan to capture Gibraltar to be rubber stamped by the Caudillo.
However, Franco felt Spain was too weak after the Civil War to join the Axis then. The country relied on imports from the Americas just to feed itself and these were at the mercy of the British Fleet, as were the Spanish Atlantic islands.
Hitler was furious but his bullying failed to get the answer he wanted from Franco. He later told Mussolini he would rather have four teeth out than deal with Franco again.
He did continue via letters and emissaries, and even Mussolini had a meeting with Franco in February 1941 to try and persuade Franco to join them.
Franco did eventually lay out two conditions for his joining the war: Britain being invaded or the Suez Canal falling.
Yet, during all this time, Franco was being advised in private by his old friend Admiral Wilhelm Canaris, head of the Abwehr (the intelligence service for the German military) not to join the Axis for Germany would lose the war.
Canaris was seen by Hitler as his Spanish expert who he often sent to see Franco. But Canaris played a dangerous double-game, working with German resistance against Hitler and the Nazi’s; in the end, it would cost him his life.
Fleming made several trips to the Iberian Peninsula during the war, glad to get away from the bickering between SIS (MI6) and SOE over Operation Golden Eye, which he had to referee.
He often travelled in civilian clothing, wearing a dark blue suit with an Etonian tie; he carried a commando fighting knife bought from Wilkinson’s - it was engraved with his name and rank on the blade. (This clearly informed the Bond character of the books, who usually carried a knife as well as a pistol.)
His fascination with gadgets extended to a fountain pen that could be fitted with a cyanide or tear gas cartridge. He took this with him as well.
In other words, Fleming was fully prepared to explore his fantasies of life as a secret agent.
In the end, Operation Golden Eye was put on alert during the Torch landings of November 1942.
But the Germans, overextended in other countries at that time, did not have the means to invade Spain and once the war moved to Sicily and Italy the danger had passed.