The revelation that a former London policeman was employed by the KGB to seduce secretaries for Cold War secrets is a reminder that sex was a potent weapon in the battle between East and West.

John Symonds's training by Russian security agents had more than a touch of James Bond-style glamour.

The former police officer has told a forthcoming BBC documentary he was "taught how to be a better lover" after being recruited by the KGB in Morocco.

Mata Hari used her seductive powers for German intelligence

"It was very pleasant. I was taught by an extremely beautiful, two extremely beautiful girls. That was quite an interesting part," he told makers of The Spying Game.

The heady cocktail of sex and spying dates back to the antics of Mata Hari, the famous German seductress who was executed by the French in 1917 for spying.

Another famous case was that of former British war minister John Profumo, who resigned after having an affair with the prostitute Christine Keeler. She was also sleeping with Eugene Ivanov, a Soviet officer.

The work of "Romeo spies", such as Symonds, forms one of the most glamorous and compelling chapters in the chronicles of Cold War espionage.

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The self-professed king is Markus Wolf, the former head of East Germany's HVA, the foreign intelligence arm of the infamous Stasi.

"If I go down in espionage history, it may well be for perfecting the use of sex in spying," Wolf wrote of his "matchmaking" exploits in his 1997 memoir, Man Without a Face.

Although all sides dabbled in the use of "Romeo spies", the HVA refined it to a degree of ruthless efficiency.

This was rooted in Wolf's belief that women were better and more useful agents than men.

Wolf realised that secretaries and personal assistants working in key ministries, political party offices and industrial companies had day-to-day access to high-level secret information.

In post-war West Germany, a shortage of men meant many of these women were unattached and therefore easier to befriend. Targeted women were usually over 30, and mostly in their 40s, says Richard Meier, former head of the West German internal security agency, Verfassungsschutz.

Christine Keeler, caused the resignation John Profumo

Wolf put his first Romeo to work in the early 1950s, after smuggling him into West Germany, and found the simple tactic reassuringly effective.

But how to bring about that initial spark of attraction? Wolf's agent, known as Felix, opted for a bus stop outside the Chancellery in Bonn. He latched on to a secretary from the Chancellor's office known as Norma, and bled information from her for years.

Meier says women were never approached at work.

"They found a reason to approach them. For instance, they came with flowers to her apartment pretending they had made a mistake; that they had the wrong address," he says.

"But they would strike up a conversation and hand them the flowers anyway.

"They would go out for an afternoon, or an evening. Sexual attraction was definitely a part of it."

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Once a "victim's" confidence had been gained, the spy would ask to see confidential files.

According to Wolf's memoir, this did not go down as badly as one might expect, and sometimes they would be offered money as an incentive to leak classified documents.

"Some women became hooked on the espionage itself - the excitement and intimacy of a shared secret - and they could be directed towards another partner if the first had to vanish for security reasons," says Wolf.

Choosing a suitable Romeo in the first place involved a rigorous screening procedure, says Wolf. But charm was always rated higher than classic James Bond looks.

Most of the men were not "experienced Don Juans, much less Adonises. They were ordinary men who might pass by on the street without attracting a second look".

Unfortunately, even professional spies were tempted to let their emotional guard down and Wolf suffered several instances where his charges fell in love.

On no account were the men allowed to marry, since most men took the identities of West Germans who were either dead or had fled the country.

If an agent got too close, Wolf would be forced to break up the relationship by recalling his agent back to the East. The other option was for love-struck Juliets to defect to the East, and several did.

Yet Wolf admits in his memoir, that playing with emotional lives in this way was destructive.

"I have to admit that in several cases the human cost was high in disrupted lives, broken hearts and destroyed careers."