Brian Witty, a former Army captain, subjected four women to sexual assaults over a 16-year period, each time being arrested after his victims reported him.
It was not until after the last attack, in which he raped a 42-year-old woman in August last year, whom he met through the website datingdirect.com, that he was charged. Lisa Longstaff, of the pressure group Women Against Rape, said the trial revealed police and the Crown Prosecution Service (CPS) repeatedly turning "their backs on women's pain".
Police said the "predatory rapist" may have attacked other women and urged them to come forward.
Witty, 41, a City financier and father-of-two, who lives in Teddington, south-west London, will be sentenced on May 25.
He faces an indefinite prison term after being convicted of three counts of rape and one of sexual assault at London's Kingston Crown Court. The court heard that when Witty's first victim, who he assaulted in 1995 at his Kensington flat, tried to fight him off, he told her: "I don't believe this, I'm a good looking bloke."
Witty attacked his second victim, a 25 year-old he had also contacted through datingdirect.com in May 2006, in an alleyway at the end of a date, telling her she was "lucky".
He attacked his third victim at his flat in October 2008, after meeting her at a City pub, where he claimed that she was "suggestively" eating a chicken skewer.
After the fourth victim went to the police, they interviewed the previous
victims again, who then gave evidence at court.
Witty denied the charges but was convicted following a five-week trial.
Edmund Gritt, prosecuting, said Witty's victims described him as a "charming, likeable, attractive, understanding, nice" man who could become "volatile". They said alcohol turned him into a man "who will not take no for an answer".
Mr Gritt told jurors that the CPS's decision not to press charges over the first three offences "confirmed in Brian Witty's mind he was untouchable and could carry on how he wanted".
Det Insp Michael Murfin, of the Metropolitan Police's Sapphire sex crime unit, said: "We want victims to have the confidence that we are here for them, will believe them and will conduct our investigations professionally."
