A court in Britain has sentenced a former schoolteacher to 22 life sentences for child abuse after using his position teaching English in Malaysia to gain access to victims.

Judge Peter Rook sentenced 30-year-old freelance photographer Richard Huckle on Monday to serve a minimum of 25 years for 71 offenses against children aged between six months and 12 years from 2006 to 2014.

The National Crime Agency arrested Huckle in 2014 and found 20,000 indecent images on his computer, 1,117 of which showed him raping and abusing children in his care. Huckle also created a 60-page "how to" guide for other pedophiles seeking to evade getting caught. He also kept a scorecard tallying the number of children abused.

Huckle groomed children while posing as a Christian English teacher and philanthropist.

It is believed Huckle abused up to 200 children from mainly poor communities in the Malaysian capital, Kuala Lumpur.

He presented himself as a practising Christian and first visited Malaysia on a teaching gap year when he was 18 or 19. He then went on to groom children while doing voluntary work.

He boasted about his crimes in online posts, saying in one discussion that "impoverished kids are definitely much easier to seduce than middle-class Western kids."

Ahead of his sentencing, Huckle claimed to a psychiatrist that he wanted to put his "madness" behind him and settle down with a south Indian woman.