London hospital's linen room, to which he had a key as a member of staff.Farrell brought the victims to his place of employment on the pretext of work experience, a court heard.
Other offending took place in the victims' homes in London and Essex, Kent, and a community centre.Prosecutors said Farrell's crimes amounted to at least 500 instances of abuse, listed as 69 offences.
The offences include attempted rape, sexual assault of a child under 13 and making indecent photographs of children. The victims were not patients at the hospital, the prosecutor said at Wood Green Crown Court.Prosecutor Paul Douglass said: "He has pleaded to 69 offences.
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