By Simon Cox
The Investigation, BBC Radio 4
Forensic experts believe there was widescale fraud on the site
Simon Bunce was one of 7,000 people whose credit cards had been used to buy pornography from an American website called Landslide.
And in May 2004, he turned up at his local police station in Hampshire to be told he was a suspected paedophile.
"I was absolutely devastated - I couldn't believe it," he says.
Simon was convinced he had been a victim of credit card fraud and set out to prove it.
And after a six-month investigation, the police found nothing on his computers or at his home.
But the damage had already been done, and he was treated as an outcast by his father.
Simon recalls: "He said, 'I don't ever want to speak to you again, you disgusting pervert', and then he told the family and they didn't speak to me for three years."
John Adam was also investigated by police for six months. Again, nothing was found on his computer, and no charges were brought against him.
Mr Adam's lawyer, Mark Spragg, says the police would not listen to reason.
"They closed their minds absolutely to the possibility that this man's credit card had been used illegally by a fraudster," he says.
Some computer forensic experts believe there was widescale fraud on the Landslide site.
"Operation Ore I think will go down as one of the worst police scandals in history," says Professor Ross Anderson, an expert in security engineering at Cambridge University, who has been consulted by the defence teams in several Operation Ore trials.
"The police just didn't look for or understand the evidence of wholesale card fraud and as a result hundreds of people, possibly in the low thousands, have had the six o'clock knock from the police...when they were just the innocent victims of credit card fraud."
Landslide was not just a single website. It was the central credit card handler for hundreds of other pornographic sites, some of them adult, with some containing images of children.
Many of these sites were run by criminals in Russia and Indonesia. These criminals would use stolen credit card details to sign up for their own websites. For each card, the website would then get a payment.
No one had no idea of the scale of the fraud as they could only see a tiny part of the Landslide database.
But last year Jim Bates, a computer forensics expert who has worked as an advisor to Scotland Yard's computer crime unit, got hold of all the Landslide records.
Within an hour he had begun to find evidence of systematic credit card fraud.
"It was that obvious...it just jumped out at you," he says.
Jim Gamble, the former head of the national crime squad and now head of the Child Exploitation and Online Protection Centre (CEOP) which has been closely involved with Operation Ore since it was first set up, defends the operation's record.
He says: "We have dealt with over 2,400 cases, over 90% of the individuals involved pleaded guilty - that's nothing about credit card fraud."
One of those cases was Richard's. He was arrested in the Midlands for a single credit card transaction.
Richard did use adult pornography, but no child pornography was found on his computers.
He maintained his innocence, but did not want to expose himself to the publicity of a trial where his friends and family would find out about the allegation.
So, like 600 others in the Ore enquiry, he accepted a caution. This meant admitting his guilt and being placed on the sex offenders register.
"The prospect of a trial with all the publicity in the local paper and your name being known was much more frightening than accepting the caution," he says.
Effect on families
There is one part of the Operation Ore story which we are not able to properly tell - the effect it has had on accused parents with young children.
There were many families who were caught up in the enquiry, but those contacted did not want to be interviewed.
David Campbell can understand why. He is a solicitor who has dealt with around a 100 Operation Ore cases.
"I've had clients who have had to agree not to live at home, not to have access to their children - there was no evidence to prosecute them or that they were a danger to their own children," he says.
The police admit they have made mistakes, but Mr Gamble stands by what Operation Ore has achieved.
He says: "Let people who are paid to make those judgements, who are trained to make those judgements, make a finding. Thus far, the findings have been massively in our favour."