Agent Fifi test for wartime spies
To the lonely would-be agent preparing for a possibly fatal mission behind Nazi lines, the glamorous Frenchwoman with the confiding manner offered the enticing prospect of some friendly female company.
But the elegantly-dressed journalist who haunted the bars of upmarket hotels in wartime England was not all that she seemed.
"Marie Collard" was an "agent provocatrice" employed by the Special Operations Executive (SOE) - Britain's Second World War sabotage organisation - to test out trainee agents before they were sent out to occupied Europe.
And as her official file released today by the National Archives in Kew, west London, makes clear, all to often Agent Fifi - as she was codenamed - succeeded in getting them to "spill the beans" and reveal who they really were.
Collard was not even her real name, but part of an elaborately constructed false identity created by British spymasters.
Born Marie Chilver - the daughter of an English father and a Latvian mother - she first came to the attention of SOE in 1941 after she helped a badly injured British airman shot down over France escape back to England, having first escaped herself from a prison camp.
Surprisingly perhaps, the RAF man - a Flight Lieutenant Simpson - far from being grateful to his rescuer, suspected she was a German agent. He said she looked too healthy for someone who had been in a prison camp and described her as "one of the most expert liars in the world".
For SOE, however, once they had established that she was not working for the Germans, she was ideal material to be an agent of their own.
In particular, she was selected as an "agent provocatrice" with the job of testing trainees at SOE's "finishing school" at Beaulieu to see if they were capable of maintaining their cover stories without compromising their mission.
A SOE report from October 1942 noted: "Her appearance is, I think, too striking and foreign for English tastes, but in my view she is suitable for use with the Beaulieu students who are nearly all foreigners.
"She could not however without considerable modification of her dress and make-up be used in less elegant surroundings than those of the more expensive or flashy hotels and bars."
Typically she would be used to approach recruits while they were on undercover training exercises to see if she could get them to talk - and all too often she succeeded. A hapless agent, codenamed Parker, was a case in point.
"Parker never showed any signs of suspicion at all with the possible exception of refusing (rather apologetically) to mention the name of his training school," she reported after her "pick-up" at the Midland Hotel in Birmingham.
"Throughout the conversation he does not seem to have been aware that he was being questioned methodically and maliciously, although I tried to make it as obvious as possible."
With one trainee after another falling victim to her wiles, Fifi began to show signs of tiring of her own success - as well as feeling sorry for those she had deceived.
"I am disappointed find that once again the obvious and primitive trap ... has worked. I am at times inclined to think the use of so malicious a ruse distasteful," she wrote.
Nevertheless she insisted there was an "absolute fairness " to her methods, arguing that it would help those trainees who did get through to "outwit all the Fifis they are likely to meet in their future career".
"Compared to what is most likely to happen in the field, it is very mild and innocent. It would be a pity to have to give up this method, because it does give the students a good chance of using their brains (or just their low cunning)," she wrote.
As time went on, however, it appeared that the trainees were getting wise to her methods. A report from September 1943 noted: "It is evident that many students resist her blandishments and only open out when they get the impression from Fifi that the exercise is over and that they can now talk."
:: Marie Chilver's file is among 3,300 intelligence and security files from the Second World War being made available for the first time online by the National Archives. Files previously only available in the National Archives reading rooms include those on the Fascist leader Sir Oswald Mosley, the Nazi propagandist William "Lord Haw Haw" Joyce and the atom spy Klaus Fuchs.