A "predatory" paedophile who kept a "sickening" account of his abuse has admitted a string of offences including 10 counts of rape.
Michael D'Costa, 64, of Farnborough Close, Wembley, north west London, appeared at Isleworth Crown Court charged with sexual offences against children and pleaded guilty to 25 offences, the Metropolitan Police said.
D'Costa was arrested after a man in a wheelchair approached a 13-year-old girl in March last year in an Asda car park at the Chalkhill Estate in Wembley and showed her an explicit video of himself engaged in a sexual act with a child.
The Met said the man then offered the girl money to have sex with him at his flat. She refused.
Concerns were raised by a teacher of the girl who contacted the police after she heard her discussing what had happened.
Officers visited D'Costa's home after his distinct description matched that of the suspect.
Police said the address contained a large amount of electrical equipment, including several televisions, laptops, computers, mobile phones and internal and external CCTV cameras.
D'Costa quickly accepted that he was the man who had been in the car park in March, adding that he had also been in relationships with other young children.
The Met said he was subsequently arrested and taken into custody.
A search found detailed diaries of his sexual interaction with three girls over a number of years as well video footage.
The accounts included the identity of the three victims and officers were able to track them down.
On December 6 2014, D'Costa was charged and remanded into custody.
Today, police said he pleaded guilty to the following offences: Five counts of rape, f ive counts of rape of a child under 13, eight counts of sexual activity with a child, two counts of causing a child under 13 to engage in sexual activity, three counts of assault on a child under 13 by penetration, and two counts of attempted rape of a child under 13.
Investigating officer Detective Inspector Neil John, of the Met's sexual offences, exploitation and child abuse command, said: "D'Costa is a predatory paedophile who kept a sickening account of his abuse on is young victims.
"Despite his first victim not wishing to pursue this matter, officers launched an investigation and this case demonstrates the Met's commitment to bringing to justice those who commit such abhorrent crimes against children.
"We are appealing to the public in case there are any further victims of D'Costa's abuse. Please come forward."
Police said he will be sentenced on Friday June 19 at Isleworth Crown Court.