James Carvell, 38, of West Street, Warwick, had pleaded guilty to 21 charges of making indecent images of children and one of possessing 115 still and 43 moving images.

Carvell, who has been living at an address in Radford Road, Leamington, as a bail condition, was jailed for six months, ordered to register as a sex offender for seven years and made subject to an extended period of three years on licence after he is released.

Prosecutor Louise Pierpoint said that in June 2002 Carvell's wife Nadege discovered pornographic pictures of children on his computer and challenged him about them.

He gave her an explanation which she accepted at the time, but then on two further occasions she discovered similar images, and again challenged him about them.

She told him that if she ever found any more she intended to go to the police, and Carvell claimed he was saving them so he could go to the police himself about them.

It was at Mrs Carvell's instigation that the police eventually went to their home in December last year, and she handed over five of Carvell's computer discs and two CD roms.

Carvell claimed it had been his intention to take them to the police to bring the web sites to their attention, but that on the first occasion his wife had confiscated them - so he had downloaded them again.

Mrs Pierpoint said that of the 42 moving images, one of which lasted 14 minutes, three were of level five, which is defined by the Court of Appeal as showing acts of sadism.

A further 25 were of level four involving penetrative sexual activity between adults and children.

Others were of less serious levels, but included other sexual activity between children and between adults and children, and some only involved erotic posing.

The 115 still images included material from all five levels of seriousness, and although most were of level one, there were more than 20 of level four.

Simon Ward, defending pointed out that the three level five moving images were all the same clip which had been downloaded three times, and although it showed a girl tied up, it was not to make her suffer but an act of bondage.

Mr Ward said an unusual feature of the case was the way it had come to light.

"It is plain from Mrs Carvell's statement that she knew of the existence of images like this from an early stage and was being told, and he insists it was true, that he would go to the police.

"She kept taking them for her own purposes. She was holding him to ransom with the discs. She told him they were in the house, and he feared she would use them to incriminate him. He was in terrible fear about what she was going to do.

"He says the reason he downloaded them was that he found them inadvertently while looking for adult pornography, and wanted to show them to the police. 

"He describes a domestic situation which was extremely unpleasant. He says if he went to the police and tried to call his wife's bluff, that would make things an absolute misery for him at home."

Jailing Carvell, Judge Marten Coates told him: "I take into account what for you would have been the dramatic circumstances in which these matters came to light.

"But I sit here day in and day out, and the material I have seen is much worse than most of the material I have been shown in the last few months."