A prolific paedophile is facing years in jail after he admitted 45 sex offences against children in Britain and abroad.
Retired English teacher Mark Frost, formerly known as Andrew Tracey, 70, pleaded guilty at the Old Bailey to a catalogue of abuse against nine children in Thailand between 2009 and 2012.
Frost raped impoverished Asian boys and encouraged them to engage in sex acts on a webcam after he groomed them with cash, sweets, computer games and swims in his pool.
He skipped bail to avoid prosecution in Thailand but was extradited from Spain last year after his activities were uncovered by Dutch police in web chats with a man in the Netherlands.
He got the boys aged between 10 and 14 to give thumbs-up signs and make love heart gestures with their hands while being filmed on a webcam engaging in sexual acts.
The Dutchman they knew as Simon watched the abuse and made suggestions for what they should do to each other from afar, the court heard.
Frost admitted a raft of charges including multiple rapes, sex assaults, inciting children to engage in sexual activity and making indecent pictures.
Since the allegations emerged in Asia, two former pupils of a school in Worcestershire have come forward claiming they were sexually assaulted in the 1990s.
Frost had sex with the boys in a school store room, during breaks, and at his home where he lived with his adopted son, and also at a car park in Woking, the Old Bailey heard.
One of the victims died before his abuser was brought to account while the other said in a statement he had "lived in fear" every day since.
The National Crime Agency believes Frost may have assaulted many more youngsters he had contact with through his 25-year career in schools in east London, Hertfordshire and Worcestershire and as a senior Scouts volunteer.
Frost was brought to justice through a complex international investigation involving the NCA and authorities in Thailand, the Netherlands and Spain.
In 1978, he subscribed to the Paedophile Information Exchange (PIE), an international organisation of people who traded obscene material.
In 1986, the unmarried teacher tried to adopt a son through the Catholic Church and was turned down, only to succeed through a local authority, the NCA said. The pair are now estranged.
Having joined the Scouts in 1967, he reached a senior position but resigned in 1991 before his first conviction.
In 1992, he was fined for possessing indecent photographs of a child and the following year was jailed for a year for allowing his premises to be used for drugs and sex with an under-age girl.
Three years later he was banned from teaching by the Department for Education.
In 1998, he was jailed for a year for indecent assault on a male under 16 and put on the sex offenders' register for 10 years.
There followed an 11-year gap in known offending during which time Frost moved from place to place, the NCA said.
Police in Guernsey began an investigation into Frost in the early 2000s under the international Operation Ore probe into indecent images of children on the internet.
Once he was taken off the sex offenders' register, he moved to Thailand where he groomed children for sex and threatened them with violence if they told anyone.
Prosecutor Sally-Ann Hales QC said images and web chats seized from Frost's Dutch contact featured 15 boys, nine of whom were identified and interviewed.
On discovering the abuse, the boys' mothers expressed their "sorrow" at finding out the man they regarded as a "kind and generous foreigner" had taken advantage of their children.
One of the youngsters was "too ashamed" to tell his mother and had gone from being a "bubbly, happy boy" to being "withdrawn and sometimes aggressive", the court heard.
One parent said: "I drown in sorrow about what Andrew (aka Frost) did to my son and other boys."
Thai police searched Frost's home following a complaint by one of the boys and found 285 indecent images which were not included in the charges.
Before he could be prosecuted in Thailand, Frost returned to Britain where police were unable to act in the absence of a warrant.
He then fled to Spain via France but was extradited from Alicante to the UK last year.
Police in Spain who examined his laptop uncovered 1,105 indecent pictures and videos, including some of white toddlers.
:: The NCA and NSPCC have set up a helpline for other victims to come forward. The number is 0800 328 0904.