A man has admitted using internet auction site eBay to build a customer network for a collection of child porn.
Giles Forbes, 41, used "low-level material" to contact people interested in indecent images of children, Blackfriars Crown Court heard.
Explicit images from a stash of stills, DVDs and videos would then be offered.
Forbes, of North Kensington, west London, admitted three counts of distributing child pornography. He will be sentenced at a later date.
Forbes also one admitted a charge of "possession for show" between 15 October 2005 and March last year.
The court heard dozens of people responded to his adverts but police believe he dealt with thousands of people over a period of 15 years.
Once contact was made the clients were offered images from his personal collection which almost filled his home, prosecutors said.
Tom Wilkins, prosecuting, said his extensive library featured children as young as seven being abused by adults.
He said: "This case is really at the most sadistic end of material the court sees of this nature.
"In fact his home was choc-a-bloc from floor to ceiling with child pornography."
The court heard that during a raid at his home officers also found an imitation handgun, handcuffs, a number of condoms and a "decommissioned but genuine" Stirling machine gun.
Forbes was convicted in 1992 of possessing child porn with intent to distribute it.
He was fined £500 but was jailed two years in 1994 when he received a six week sentence for importing images of pre-pubescent children being abused. Forbes was jailed for six months in 1999 for a similar conviction.