A man who spent years making child porn images "of the worst kind" has been jailed for 10 years and banned from returning to his north London home.
McDonagh's home overlooked two schools
Raymond McDonagh, 42, pleaded guilty to 15 offences, including two attacks on a 13-year-old boy in 1984 and 1985.
A search of his flat yielded 13,500 pictures of youngsters and video clips, Southwark Crown Court was told.
McDonagh faces a lifelong ban from the Hilldrop estate in Holloway, and the local primary and secondary schools.
Described as a "trusted lieutenant", he acted as a sort of "online" librarian in an Internet paedophile ring, the court heard.
The investigation found that under the name Reamoin - the Gaelic spelling of his name - McDonagh used a piece of software called ICQ ("I seek you") allowing others online to share picture and video files.
During their search, officers also took away a pair of binoculars found next to a window overlooking the two local schools.
"Society expects the courts to pass sentences to deter those who may be tempted to involve themselves in such depraved activity," said Judge Stephen Robbins passing sentence.
"This case illustrates only too clearly the impact of computer internet porn and the high level it has reached in this country and elsewhere."
Police appealed for the victim of the assaults in the 1980s, committed in the Thamesmead area of south east London, to contact police, as they suspect McDonagh may have harmed other children.