Popov's serum of truth...

Sometimes a good book will surprise but a lack of accuracy. Estoril loas Años Dorados, by Ricard Mateos Saínz de Medrano is a masterpiece in the art of telling the way the royal heads and other nobles lived in Cascais and Sintra during WW2. Places, people and events are described in an attractive despite sometimes in a repetitive way. But the reader feels the very ambiance and see History on the making.
For my research it's an impressive tool. But what astonishes is to read things like that in 1941 Ian Fleming and "Dusko" Popov had rooms at Hotel Palácio and the first injected the serum of the truth to check if the second was a loyal spy.
It is true that Commander Fleming, with his Chief Admiral Godfrey, both working in the Naval Intelligence Divison, arrived in May 1941 and found a room in Hotel Palácio. And it's also true that the Serbian Dusán Popov, a commercial lawyer working for the Germans as agent Ivan and for the Brits as Tricycle was also in the same Hotel for several times. And true as well it's that after his retirement from NID Fleming's first novel Casino Royale was in a way inspired both in a Casino - but not the sombre one in Estoril and in 007 James Bond has some features of Popov's, mainly the glamour.
But what is completely unreal is the story of the serum of true. And not necessary if I may say it!