On a cold, cloudy December day in 2002, Jonathan was about to take his class of children to chapel. His life as he knew it was about to end.
His headmaster appeared at the door and asked him to go with him. "There are two policemen who want to talk to you," he said.
The school where Jonathan taught geography was an unlikely place for police officers to turn up. A private prep school set in extensive grounds, it offered education to boys and girls from nursery age to 13.
Jonathan had a secret life. Living alone, he didn't think he would be unmasked. "I'd been trying to be as private and quiet as possible. I had two separate lives."
His dark side was about to be exposed. The waiting police told him they had found online payment records linking him to child abuse websites.
"I admitted it straight away," he recalls. "Once the game was up there was no point trying to hide it."
He was stunned at being exposed. He had heard about paedophiles being arrested but thought he was different. "I thought everything was very personal, all kept in my own mind and computer. It was a devastating shock to see I had been found out."
That afternoon he watched as a team of officers searched his home, a prefabricated building in a secluded spot in the school grounds. They took away his computer and VHS cassettes to a police van. "I was blank. I remember feeling cold. The front door was open and they were moving stuff in and out."
He was taken to his local police station, where he was arrested and put in a cell. The news was beginning to sink in. "I thought, 'My life is at an end, what is the point?'"
Jonathan, 57, recalls being released on bail late that night and taken home by the headmaster: "He was tight-lipped. For him it must've been awful." Over the next few days, he wished he would die.
The teacher's capture was repeated in different ways thousands of times across the UK during the first decade of the 21st Century. This was Operation Ore.
Details of 7,272 Britons whose credit cards had apparently been used to purchase child abuse images were passed to officers by their counterparts in the US.
The seriousness of the allegations, the fear that children were at risk, and the sheer number of leads put huge pressure on the authorities to act quickly.
What followed was the largest investigation of its kind.
It put under scrutiny the intimate online browsing habits of individuals from all walks of life. The suspects included police officers, doctors, teachers and celebrities.
Household names like rock star Pete Townshend and actor Chris Langham were among those implicated.
Local newspapers, too, began to fill up with reports about normal-looking men who, in the privacy of their own home, were allegedly browsing obscene images of children. In the worst cases, children were shown being raped.
By the time the Ore prosecutions concluded, 1,837 convictions had been secured and 710 cautions handed out, according to the Child Exploitation and Online Protection Centre (Ceop).
The sheer scale of the operation had tested the police. "In the early days there was a feeling of being overwhelmed," admits Jim Gamble, former chief executive of Ceop.
The countless headlines these raids generated, experts believe, transformed popular perceptions of what a sex offender looked like and did.
As the reports of court cases proliferated, the public increasingly became familiar with hitherto obscure terms from the world of child protection. The Sentencing Advisory Panel scale, used to categorise indecent images for seriousness according to grades one to five, is now a regular part of newspaper court reports.
The raids coincided with mounting public concern about the amount of sexual material accessible to anyone with an internet connection.
For those behind it, the investigation was a success. It raised awareness of exploitation and led to 154 children being protected from abuse, according to Ceop.
"People thought they could go online and wouldn't be held to account," says Gamble. "They believed the internet was a labyrinth that was too difficult for the police."
Critics, however, raised questions about the police's handling of the inquiry. Some said potential credit card fraud had not been properly investigated and the reputations of innocent men had been destroyed as a result. Others feared the inquiry had contributed to an atmosphere of moral panic in which paedophiles, or potential paedophiles, lurked in every corner.
What is clear is that Ore helped define Britain's relationship with the internet at a time when its use in people's homes was exploding. As recently as March 2003 just 15.3% of people had broadband, according to the Office for National Statistics. By this year, Ofcom put the figure at 76%.
The raw material of Operation Ore came from the US.
In August 1999, dozens of US law enforcement agents raided an office and a house in Fort Worth, Texas. They belonged to Thomas and Janice Reedy.
|Thomas and Janice Reedy|
The company provided a portal to about 3,000 sites as well as online payment services. Among those using its systems were a number of third-party sites, typically hosted outside the US, offering images of child abuse.
One site connected with Landslide was called Child Rape. A series of pictures linked to from the site showed fathers having sex with their own children.
A jury found Thomas Reedy guilty of trafficking indecent images of children in January 2000. He was sentenced to 1,335 years in prison - later reduced to 180 on appeal - and Janice Reedy to 14.
180 years instead of 1335; that must feel a lot better.
In the wake of the raids, US authorities set up an investigation called Operation Avalanche to examine the 35,000 names on Landslide's database. The Federal Bureau of Investigation then shared the details of subscribers from overseas with law enforcement agencies in the relevant countries.
There was Operation Snowball in Canada, Operation Pecunia in Germany, Operation Amethyst in Ireland and Operation Genesis in Switzerland.
When more than 7,000 names of British suspects were passed to UK authorities, it quickly became apparent that investigating them would be a huge undertaking.
For the rest of this article, see: http://www.bbc.co.uk/news/magazine-20237564