Peter Davies, head of the Child Exploitation and Online Protection Centre (CEOP), said there was now a "class of child abusers very proficient in technology" who are consistently trying to evade authorities by finding new means of accessing children.
Speaking to Daybreak, he said: "The old model, with a view of meeting online with a view to meeting offline and then physical abuse taking place is actually a diminishing, these days sexual abuse of children can take place purely online."
More top news
Old Labour firebrand Derek Hatton is now locked in a new fight - to rejoin his old party.
After a career which began with carrying Britain's first nuclear bombs, the last flying Vulcan Bomber is being retired.
Tonight will see further showers across northern Britain, whilst Wales sees rain arriving overnight pushing eastwards to many central areas