Cold War fears revisited with reprint of booklet
Their Trade is Treachery was published by the Central Office of Information in 1964.
The advice came after the resignation of Secretary of State for War John Profumo, following a relationship with Christine Keeler who was also linked to Yevgeny Ivanov, a senior naval attache at the Soviet embassy in London.
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Hide AdThe scandal prompted concerns about the risk of sensitive information being passed to Russia.
The leaflet warned that enemy intelligence services would exploit a person's weaknesses and use "unashamed" blackmail against their target.
"On the whole, guile, patience, and enticement are employed by enemy Intelligence Services operating in Britain when recruiting agents," it said.
"Defects of character are sought, venality, idealism, and innocence are exploited."
The booklet features true case studies of spies and their victims.