A PAEDOPHILE is likely to die in jail after being handed 13 life sentences for a "horrific" catalogue of abuse on children in Britain and abroad amid fears the full scale of his crimes have yet to emerge.

Retired English teacher Mark Frost, formerly known as Andrew Tracey, 70, pleaded guilty at the Old Bailey to 45 sex offences against nine children in Thailand between 2009 and 2012.

He also admitted having sex with two pupils in Worcestershire over three years in the 1990s.

On some occasions, the abuse happened on school grounds and on others, unmarried Frost's adopted son was present, the court heard.

He was sentenced today by Judge Mark Lucraft to serve a minimum of 16 years for each life sentence.

Other determinate sentences were ordered to run concurrently.

The judge told Frost he was responsible for "the most appalling catalogue of sexual abuse" and it was clear he had an "ongoing obsession" with young boys.

He said: "Your conduct towards each and every one of these victims is horrific and deeply disturbing."

Commenting on the sentence, an NSPCC spokesman said: “Mark Frost’s vile campaign of sickening child abuse spanned over quarter of a century in the UK and abroad and today’s sentence will likely see him spending the rest of his days behind bars.

“Frost was a prolific and dangerous paedophile who worked as a teacher and Scout leader for decades.

"We hope that anyone who suffered can now find the courage to speak out.

“The NSPCC has worked with the NCA to set up a helpline – 0800 328 0904 – for anyone who thinks they may have been affected by this case. We will get them the help and support they need.”