At least 80,000 people in the UK pose a sexual threat to children online, the Home Secretary is set to reveal.
Sajid Javid will announce the figure and describe his shock at discovering the scale of the danger posed to children on the internet.
In a flagship speech, he will outline his "personal mission" to tackle child abuse in all its forms.
Peter Davies from Get Safe Online said that he was “not surprised by the figure” and that there were new offenders appearing all the time.
Talking to talkRADIO’s Julia Hartley-Brewer, Mr Davies said: “It is an accurate estimate. In 2012 we came out with an estimate of 50,000 and we worked as hard as we could to make it as accurate as it could be.
“I am not surprised by the figure and I am sure it is well backed up and that is enough of a job for law enforcement, for social services, for the tech giants, to grip.
“There are new offenders appearing all the time and tragically there are new images appearing all the time which means more abuse being committed.”
‘The full horror of the scale’
Other new statistics reveal referrals of child abuse images to the NCA have surged by 700% in the last five years.
Images are also getting more graphic, with abuse of babies and children under 10 more regularly documented, the Home Office said.
Mr Javid is expected to say: "It was when I visited the National Crime Agency's Child Exploitation Online Protection Command that the full horror of the scale and evolving nature of child sexual abuse was really brought home to me.
"One officer I met, who had previously worked in counter-terrorism for over 20 years, told me how in all his years of working he's never been so shocked by the scale of the threat or the determination of the offenders as he is in his current job."