A judge who jailed a Carlisle man for "despicable" online sex crimes has pleaded with authorities to take urgent action and "protect our children".
His Honour Peter Davies spoke out after locking up David Nelson Mitchell for nine years and four months at the city's crown court.
Judge Davies heard how 49-year-old Mitchell repeatedly preyed on two girls over Skype by pretending to be a teenage boy.
He then set up further fake profiles as he blackmailed his victims and threatened to expose their intimate acts.
Mitchell, who admitted seven child sex crimes, was told his offending had been "despicable, nasty and brutal".
Passing sentence, Judge Davies called for social media sites - and private chats - to be rigorously monitored by authorities.
"There should be systems and methods in place that expose and identify people like you before you are allowed to cause these problems," he said in his address to Mitchell, of Granville Road.
"These courts plead for internet companies and organisations to police these social media devices. Let us protect our children."