A former bookseller who became addicted to child pornography has been jailed for plotting to rape three children.

Gerald Ingram used the internet to make contact with a woman and arrange to have sex with her two daughters aged three and five, and a 10-year-old boy.

The 63-year-old did not know that the woman was a covert police officer setting up a sting operation after becoming aware of his intentions to molest youngsters. The children she told him about were fictional.

Police later found on Ingram’s computer hundreds of indecent images of children. They included pictures rated in the highest offence category by child protection experts.

Ingram, of Highgate, north London, had also sent emails and instant messages to the woman in preparation for meeting the children.

You pose a high risk of harm to the public

At Southwark Crown Court on Wednesday, prosecutor Lesley Jones said: “He made very explicit mention of what he wanted to do, especially to the little girls.”

In May, Ingram met the woman in a park, thinking she would take him to the children. He brought a bag containing sweets, two soft-toy dogs and other items he intended to use to lure the girls.

During the meeting, the undercover officer pointed out a small child who was playing in the park. Ingram said the girl was “beautiful” and became aroused.

Two plain-clothes officers swooped to arrest him as he prepared to leave with the woman. He later admitted four charges relating to distributing the indecent images and arranging the potential sex acts. A number of similar charges will lie on file.

John Dye, defending, said Ingram had denied intending to “go beyond anything other than indecent assault”. Sentencing him to three years and eight months in jail, Judge Nicholas Loraine-Smith told Ingram: “You were certainly anticipating sexual contact with those children. The fact remains that you pose a high risk of harm to the public.”

On his release from prison, Ingram will be forced to sign the Sex Offenders’ Register for life. A sexual offender’s prevention order will bar him from using devices which provide internet access and from having contact with children under the age of 16.

Director of Jewish Prison Chaplaincy Rev Michael Binstock was in court and has been offering spiritual guidance during Ingram’s time on remand.

Residents in Priory Gardens, Highgate, painted a picture of a man whose life had spiralled out of control.Ingram had been a popular neighbour, described as “kind” and “generous”, who had cared for his elderly mother before she died around three years ago. But he was also described as “eccentric” and “weird”.

After losing his job his home fell into a state of disrepair.