An accountant told the police officers who were raiding his home that his collection of child pornography was there for ‘academic reasons’.

Alan Moore, of Chequers Walk in Waltham Abbey, has been jailed for 18 months after he was discovered with more than 16,000 illegal images and 420 videos on his laptop computer and on floppy discs.

Dozens of the images showed children being sexually tortured.

At Chelmsford Crown Court, Recorder John Caudle, said: “A substantial number of the children were clearly under 13, and some were as young as three or four years old.

“A number involved bondage of very young girls and there was distress on the faces of a number of girls.”

Samantha Lowther, for the prosecution, said that police raiding Moore’s home had explained to him that they were investigating internet activities and file sharing.

He replied: “I've seen them on there. It’s only for academic reasons. I was curious.”

Miss Lowther said there was no evidence he had shared the images or shown them to anybody.

But she pointed out that Moore, 54, had been given a two-year conditional discharge in 1985 for indecent assault.

Moore’s counsel, Andrew Fitch-Holland, said: “He's married, works for a chartered accountants, and has a number of keen interests – primarily computers.

“He’s had a healthy sex life during his marriage, and does not shy away from his interest in bondage and sadomasochism, a fact for which he and his wife can’t be criticised.

“Effectively he came across what he described as a Pandora’s Box through a one-way download – sent to him. He has a broad sexual appetitite.

“He accepts his behaviour was reckless but not malelovent. There was no contact with any child – its fantasising.”

Moore pleaded guilty to five charges of downloading still and movie pornographic images of children.

Recorder Caudle imposed an indefinite sex offenders prevention order and ordered him placed on the sex offenders’ register for life.