A stash of child porn was found by police after mechanics found an indecent image in a customer's car.
Peter Wingham, 60, was later found to have 500 indecent images of children on his computer.
He was this week spared jail after a judge described him as "extremely fortunate."
Wingham was using his computer when police executed a search warrant at his home in December 2011, Lincoln Crown Court heard. The court was told Wingham admitted what he had done straight away when a police officer knocked on his door and asked him if he had a computer.
Justin Wigoder, prosecuting, said Wingham replied to the officer: "Yes it's upstairs, it's on. I better come clean and explain. I have some stuff on it now."
When the officer asked if it was children Wingham answered "yes", Mr Wigoder added.
In total, police found 543 indecent images of children on the computer which included videos. The court heard police had been led to Wingham after mechanics found a print of an indecent photo in the boot of his car.
Of the 543 images 368 were at level one, the lowest seriousness, 72 at level two, eight at level three and 91 at level four. No images at the most serious category of level five were found.
Wingham admitted what he had done during police interview telling officers he was "devastated." Wingham said he had stopped looking at the images for a period but had then relapsed.
Mr Wigoder said Wingham admitted to the officers: "It's going to change my life but I've got to say I've been expecting the knock at the door."
The court heard Wingham had no previous convictions and had been "very respected" in the equestrian business for many years.
Wingham, of Lancaster Drive, Market Rasen, pleaded guilty to having 543 indecent photographs of children in December 2011, two charges of making an indecent image of a child in 2008 and again in 2010. He also pleaded guilty to six charges of making an indecent video of a child in November and December 2011.
He was sentenced to a three year community order in which he will be under the supervision of a probation officer, ordered to complete the sex offenders' treatment course and made the subject of a sexual offences prevention order for five years.
Passing sentence, Judge Michael Heath told Wingham: "It appears when your marriage broke up you turned for sexual satisfaction to adult pornography. You then began to download child pornography."