Margot Asquith was known within the family to be highly demanding and critical. Poor health frequently made her "difficult". There were rumours she was a "sapphist". The young Anthony's early experience of his mother was punctured with her capacity for making terrible scenes. People become masochistic, Freud said, as a way of suppressing their desire to sexually dominate others. Anthony Asquith was 61 years old when he is rumoured to have paid for Mariella's services. He was unmarried and his friends wondered if he was homosexual. They puzzled over his weekend hobby of serving tea at a lorry drivers' café near Catterick, in Yorkshire. They wondered if it signified an escape into anonymity à la T. E. Lawrence's forays into the desert. The desire to submit, Freud argued, arises from guilt over the desire to dominate. Asquith's mother was most formidable. Mariella, the dominatrix, had an unerring instinct for the weaknesses of men. But did her client list include the youngest son of the Home Secretary who had signed the "gross indecency" arrest warrant against Oscar Wilde? Asquith, his closest friends say, was happily ensconsed in a relationship with a working-class East End chap who was married to a most accommodating lady, with whom Asquith had an affectionate, almost familial, bond. It is unlikely that Asquith was her client.

With each addition of pain or restraint, the man in the mask would stiffen slightly. Then he fell into a deep calm, waiting only to obey his mistress.

I have spoken to the man who burgled Mariella's flat in 1977. He did so under the auspices of my grandfather, a conman whom Mariella was investigating for Special Branch. By the 1970s her heightened sense of drama had led her into an equally rarefied field of work. Mariella now styled herself an agent provocateur. But Tricky Dicky was most struck by a manuscript he found that dated to this earlier period of his life. Next to the words "man in the mask", were the initials "P.P."

The truth will never be known, and no one really cares now. If controversy rekindles it is because of the suspected cover-up and infamous mistrial that took place. Stephen Ward had let his penchant for parties develop into a blackmailers' charter. A man with a taste for the high life has to pay for it somehow. Those closest to Ward knew that he kept a stash of pornography, including photographs of a compromising nature. These photos were made to order and of special people, a source close to Ward tells me. Ivanov boasted to Mariella about the Politbureau's stash of Porn that he had obtained for them. "I have all of them!" he gloated. He made special reference to the following, "including ‘a tall, blond man of Greek origins' and his daughter".

"Everyone went home well satisfied," were the last words the "Government Chief Whip" had to say about her party. In December 1961 she was at the top of her game. Two years later, her taste for theatricals crystallised the public's notion of a British Empire in decay and a government run by elderly degenerates. The game was up. Mariella's clients were running for cover as the "gross indecency" trial of her day found Stephen Ward and, indirectly, his associates guilty of immorality. What was a girl to do?

One of Mariella's most endearing traits was her resilience. Tired of the hassle that the aristocracy and politicians carried with them, she started frequenting the dens of Soho. Villains were her latest quarry, and — typical Mariella — she dug away until she dredged up one of the best — Agent Zigzag. And so she began the next episode of her strange, thwarted and yet triumphant, secretive life.