A British serial paedophile who preyed on impoverished Kuala Lumpur slum children voiced deep remorse before a London court on Friday for his "disgusting behaviour". Richard Huckle, 30, who has pleaded guilty to 71 of 91 counts of child sex offences, including rape, targeted children while posing as a volunteer working with Christian communities in the Malaysian capital. More than 20,000 images of child sex abuses were found on his heavily-encrypted laptop. Huckle appeared in the dock at London's Old Bailey criminal court where judge Peter Rook heard mitigation from his lawyer Philip Sapsford. Rook said he would have to weigh up whether a life sentence was appropriate for 22 of the most serious counts before passing sentence at 10:00am (0900 GMT) on Monday. Sapsford asked for leniency, arguing that in pleading guilty, his client had spared a jury from being exposed to images of his abuse. He accepted it would be "a very long time" before Huckle was released from prison but asked that the sentence give his client "hope" of rehabilitation into society. Huckle had bragged about his abuse online and was snared by an Australian investigation on the dark web -- a hard-to-access part of the Internet often used for illegal activity. - 'All my own doing' - In the letter of remorse written on May 23 and read to the court by his lawyer, Huckle acknowledged "the scale of the damage I have caused". "I completely misjudged the affections I received from these children. "My low self-esteem and lack of confidence with women was no excuse to be using these children as an outlet." He said he was "gullible to be easily influenced" by the "pathetic, perverted lust of those who drew me into the dark net". And he said he hoped there would be help for the victims of the "disgusting behaviour I performed on them". "I am open and eager to rehabilitate from this offending behaviour," he wrote. "In no way do I want to be treated as a martyr to child sex tourism in Malaysia. "This was all my own doing as a consequence of my own immaturities. "I am deeply remorseful and regretful of what has happened and will do all I can in being proactive towards rehabilitating myself." The Old Bailey heard earlier that Huckle targeted poor victims and was writing a guide to child abuse that he intended to publish for profit. He posted pictures of the abuse of boys and girls online. Huckle admitted offences against children aged between six months and 12 years, committed between 2006 and 2014. Investigators have identified 23 victims -- 22 Malaysians and one Cambodian. - Outrage in Malaysia - Huckle, who comes from Kent in southeastern England, was arrested at London's Gatwick Airport in December 2014 as he returned from Malaysia to spend Christmas with his parents. Files on his laptop showed him committing offences including rape. Huckle has not handed over the passwords for some files which remain encrypted. Police also found a ledger in which he detailed the abuse of 191 victims, but officers were unable to press charges on all cases as there was no photographic evidence. Videos recovered showed children being forced to sexually abuse each other, abuse being committed as other children watched and children being urinated on. The case has sparked revulsion in Malaysia, with newspapers on Friday plastering photos of Huckle on their front pages along with angry headlines. "This monster defiled our kids," read the headline in The Star leading daily. Huckle took children with him to church and regularly roamed an impoverished Kuala Lumpur neighbourhood to snap pictures of children, those who had met him said on Friday. But several people interviewed by AFP said they had seen no reason to suspect Huckle of child sex abuse. Paul Packianathan, senior pastor of a Protestant church located in a Kuala Lumpur suburb, said Huckle's church visits were infrequent and had aroused "no suspicions". He condemned Huckle's actions as "despicable".