A man has been jailed for 11 years after he admitted persuading a father to rape his two-year-old daughter and send him pictures of the abuse.
Father-of-two Pemberton's marriage ended after his arrest
Posing on the internet as a nurse, Alan Pemberton, 55, promised to put the man in touch with a father who would let him have sex with his teenage daughter.
Pemberton, of Kennington, south London, pleaded guilty to a number of child sex offences including incitement to rape.
The father had earlier been jailed for three years for his part in the abuse.
Passing sentence on Pemberton at London's Middlesex Guildhall Crown Court, Judge Roger Chapple said he had dealt with many cases of child pornography but found these images "particularly upsetting".
He told Pemberton: "You, through your plea, can accept the obvious truth that had it not been for your urging, your encouragement, your incitement, these acts would never have taken place."
Prosecutor Anita Arora told the court: "This case is to do with a man using the Internet to hide his identity and to contact people, like him, paedophiles who have an unhealthy sexual interest in children."
The father believed he was chatting online to a nurse named Holly Chadwick.
Pemberton persuaded the other man to send him photographs of the girl being assaulted.
The second man was arrested in February 2005 by Wiltshire Police, who alerted Scotland Yard's paedophile unit.
Barry Kogan, defending, said: "He was trapped for many years in an unhappy and loveless marriage and so the internet for him became a private outlet for his feelings of isolation and frustration."
Since his arrest, Pemberton's marriage of 34 years had broken down and he had become estranged from his two grown-up sons, the court heard.
Pemberton felt he had "wrecked his own life and the lives of his family", Mr Kogan added.
In 1997 Croydon magistrates gave Pemberton a two-year probation order for making a series of nuisance telephone calls to females - one as young as nine and another in her 80s - in which he pretended to be a doctor and asked them intimate sexual questions.