Former Army captain Brian Witty, 42, had denied raping three 19-year-old women who came forward after seeing reports of his conviction last year for another string of sex attacks.
But a jury at Kingston Crown Court in Surrey today found Witty, originally of Teddington, Middlesex, guilty and he was ordered to serve a minimum of 12 years of his life sentence.
He had already been jailed indefinitely in May last year for three counts of rape and one of sexual assault by penetration.
The attacks he was first convicted of took place between 1995 and 2011. They were on victims the predator met though a dating website.
The first of these offences took place in 1989 when both Witty and his victim were 19-year-old A-level students at a Hull college. They began a relationship which ended when the two began studies at different universities.
Tracking her down to her halls of residence, Witty entered her room unexpectedly, raped and repeatedly punched her.
He struck again in 1997, when he was aged 27. First, he attacked a 19-year-old who was staying at his sister’s home in Hull after the two women had been out together.
Then, at the end of New Year’s Eve celebrations, he lured another 19-year-old to his flat in Kensington, west London, with an offer of accommodation for the night before raping her there.
He was arrested on January 24 this year for the three more offences and charged on February 12.
Metropolitan Police Detective Constable Peter Sullivan said: ‘The women in this and Witty’s previous trial have been incredibly courageous.
‘I have great admiration for the dignity and fortitude they have shown throughout the court proceedings. Witty is a serial rapist who is arrogant in the extreme and has shown absolutely no contrition for his crimes.
‘Despite the overwhelming evidence against him, he made these women - and in some cases their families - give lengthy evidence, further compounding the distress and trauma he had already caused.
‘He has left a legacy of pain and suffering which will live with many of them for the rest of their lives.
‘The consistency of his offending over several decades shows that he will always be threat to women and therefore I applaud the life sentence which was passed today.’
Sally-Ann Russell, of the Crown Prosecution Service, said: ‘Witty’s predatory behaviour towards his victims has proved him to be dangerous and prolific sexual offender.
‘His conviction in 2012 for three rapes and one sexual assault clearly gave further victims the confidence to come forward.
‘Witty has consistently denied all the offences put before the court but for a second time the jury has seen through his lies and convicted him of his crimes.
‘Their bravery has ensured that Witty is made to face the consequences of his actions and we hope that this conviction gives confidence to other victims to report their abusers and help us bring them to justice.
‘CPS London is dedicated to prosecuting sexual offenders and supporting victims of sexual abuse.’
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