A laptop computer belonging to a solictor's clerk contained thousands of child porn images, Croydon Crown Court heard.
Julian Spencer, 54, of Davies Close, Woodside, faces a total of 22 charges, all of which he denies.
The court was told yesterday (Tuesday) that police raided his home and took away his laptop computer.
When examined by an expert it was found to have about 3,000 pictures of child pornography.
Mr Spencer faces 18 charges of making indecent images of children and one of possession of indecent images of children. The remainder relate to the incitement to distribute images.
Kevin Baumber, prosecuting, said the indictment against Mr Spencer related to the period between April 1999 and March 2004.
But that some of the pictures were shown to have been created or accessed on the day before the police raid.
Mr Baumber said Mr Spencer had also been searching the internet for material and had been buying items with his credit card.
Most of the images were of sexual poses, but some were more serious and included sexual activity.
He was arrested and taken to South Norwood police station where he told officers he had never accessed pornography of any kind, although he had accidentally come across some, for which he blamed a computer virus.
Mr Spencer denied having any interest in child pornography and told the court: "They made me throw up".
The trial continues.