More than 40 police forces have been involved in raids as part of an operation targeting suspected internet paedophiles.
Several people have been arrested in the raids which took place over the last 48 hours in the operation led by the Child Exploitation and Online Protection Centre (Ceop).
The arrests came as Ceop published a report on the risk posed by people who possess indecent images of children and recommendations about how police can protect children.
The specialist police child protection unit warns that anyone caught downloading child abuse images online poses a risk of committing physical sex attacks on children.
The images are becoming more extreme, sadistic and violent, but the severity and number of images held by offenders are not enough alone to assess the risk they pose or the sentence they should receive, the report said.
The warning comes after a watchdog claimed that serious child abuse was rife across England, saying that girls as young as 11 "expect" to have to perform sex acts on rows of boys for up to two hours at a time in parts of London.
Deputy children's commissioner Sue Berelowitz told MPs her in-depth study of the problem suggested there "isn't a town, village or hamlet in which children are not being sexually exploited".
Ceop urged police forces to prioritise the investigation of anyone caught with child abuse images who has easy access to children.
And it called for the authorities to look beyond the quantity and severity of the images, adding that a full risk assessment should be considered before a judge hands down any sentence.
The notion that any case may result in the identification of a victim should be at the forefront of every investigation, Ceop said.
"The landscape of austerity coupled with the increasing volumes of work that child protection teams are faced with in the UK is unprecedented," its report said.
Referrals to Ceop increased by 181% between April last year and March alone, figures showed.
The report went on: "This point in time has the potential to be a golden age for child protection, but the evolution of technology is likely to make the internet an increasingly difficult place to investigate.
"The predicted dramatic rise in work volumes will require a fresh look at policing priorities and the resources allocated to this area of policing.
"In a perfect world all IIOC (indecent images of children) possession cases would be subject to a comprehensive, quick time investigation as soon as intelligence comes to the attention of law enforcement.
"However in a time where resource is sparse and priorities continually modified, this has become increasingly unachievable."
But it warned: "There is a clear correlation between IIOC offending and contact sexual offending against children although causation cannot be established.
"Anyone who possesses IIOC poses a risk of committing contact sexual offences against children.
"Cases where it has been identified that an IIOC possession suspect has access to children should be actioned as an immediate priority."
Access to children was a "key factor in the assessment of an offender's risk" and the link between possessing the images and carrying out sexual attacks "highlights the need to consider each possession offender as a potential contact offender to some extent", the Ceop report found.
A study of almost 100 case studies from 34 forces found offenders who both possessed child abuse images and attacked children were "almost exclusively white males", with most aged between 19 and 45.
Those not in work, and possibly therefore those with high levels of internet usage, those working in schools or care work, and those in manual and manufacturing jobs made up most of the sample, the report said.
Jon Brown, head of the NSPCC's sexual abuse programme, said: "This supports research the NSPCC carried out last year which revealed one in three of those convicted of possessing child abuse images has also committed other serious sexual offences against children."
He added: "It's a very worrying situation and more research is needed on the most effective punishment and treatment of offenders caught viewing child abuse pictures.
"Trying to stop the terrible trade in these images is obviously a huge task.
"But it mustn't be seen in isolation. It's part of a much bigger sexual abuse problem.
"And we must never forget that these images are abuse in themselves and often very young children, including babies, are being assaulted and raped so these pictures can be produced."