A wealthy financier "taken for a ride" by a former mistress, who twice lied about being pregnant to get money from him, has won a High Court injunction against her.
The married father, who cannot be identified for legal reasons, was also awarded £100,000 in damages for payments he made to the woman during their affair.
Following a hearing held in private, Sir David Eady ruled the woman was responsible for "a consistent pattern of harassing behaviour" and would continue to cause "embarrassment and distress" if no injunction was in place.
Sitting in London on Wednesday, the judge said the man was "at least partly responsible" for putting his family's privacy at risk by his conduct.
However he said details of the affair were nothing more than "prurient gossip" and there was no public interest in the "unhappy and intensely personal saga".
The man of "considerable wealth" said he became "infatuated" with the woman when his marriage was in difficulty.
But the "scales fell from his eyes" after he discovered she had twice lied about being pregnant and having an abortion.
He said it was a "shock" to find out the truth when he went with her to an appointment for a genuine pregnancy and she told a doctor she had never previously had a termination.
By then he had given her thousands of pounds, including a large sum he believed was for living costs after she claimed to be "homeless" as a result of her ex-partner discovering the affair.
The woman did not attend the hearing last month but admitted in written statements she had not been pregnant either time and had not been homeless.
The man told the court the woman made a number of demands and sent personal information to the office where he worked - knowing his staff would see it and he would be caused "acute embarrassment".
This included screenshots of their private correspondence, after he refused to buy her a £1 million painting, and a photograph of a positive pregnancy test.
She also had three large prints he had given her, which had been defaced with "liar" scrawled across them, delivered to his office and she sent text messages to his wife during a family holiday.
Sir David said: "He now of course realises that it would have been wise to terminate the relationship much earlier, but accepts that he was still infatuated."
After discovering she had lied about the earlier pregnancies the man decided to end their relationship, but was persuaded to meet her in London.
She then took his passport and later returned it to his office with a pregnancy scan photograph attached.
Although it was not known whether he was the father, the man offered to give her £1.5 million for the child, but she demanded between £5 million and £10 million to "set her up for life".
Following a number of discussions which he found "increasingly upsetting and distressing" he confided in his wife and eventually "cut all ties" with the woman - though she continued to try and contact him.
The judge said there was "little doubt" the woman wished to reveal the background to their relationship.
He added: "In view of this, and of her regular demands for large sums of money, I cannot conclude otherwise than that she represents a continuing risk to him, and to his wife and family, of further harassment, intrusion and infringements of privacy.
"So too, one only has to recall the apparent relish with which she is still choosing to make scandalous allegations about him to appreciate the continuing threat she represents."