The NSPCC has said it is an "uncomfortable truth" that police cannot hope to pursue every person who looks at indecent images of children.
Keith Bristow, the head of the National Crime Agency, said there was no way his officers could go after all 50,000 suspects and they have to focus on the "greatest risks".
Jon Brown, NSPCC lead for tackling sexual abuse, said: "Mr Bristow reveals an uncomfortable truth about the difficult decisions officers face daily in identifying and pursuing offenders. It's true that the police can only do what they can with the budgets available to them."
"The Government must make tackling this vile trade a priority in the funding available to the NCA and at a local force level," Mr Brown added.
The Foreign Secretary has welcomed fresh EU sanctions against the Syrian regime, describing President Assad as the "cause of instability and conflict" in the country.
Philip Hammond and European counterparts agreed the measures at a meeting in Brussels today.
Another 18 individuals and entities, including some suspected of supplying the administration with oil, will be subjected to restrictions.
Among those targeted by the sanctions is a "notorious" military commander who ordered nerve gas attacks that killed hundreds of civilians.
"Sanctions are a key part of our strategy for weakening the regime and limiting its ability to perpetrate more barbaric acts against the Syrian people," Mr Hammond said.
The man suspected of murdering seven women in the US state of Indiana told police he had "messed up" by killing one of his victims in a motel.
Darren Deon Vann reportedly arranged to meet his victim at Motel 6 in the city of Hammond through a 'pay for prostitution service', Hammond police chief John Doughty said.
An acquaintance of the victim became suspicious after receiving strange messages from her phone.
She then went to the motel and discovered the body, after which she gave police a phone number leading them to Vann.
Mr Doughty said Vann had co-operated with police and was seeking a deal with prosecutors, though he would not elaborate on what the deal was.
Huge explosions were seen over the Syrian town of Kobani today as air strikes against Islamic State targets continued.
The Mayor of the town of Hammond in Indiana has said the man arrested by police over the killings of seven women "is what I would label a serial killer".
Writing on Facebook, Thomas McDermott Jr said Darren Deon Vann was also a convicted sex offender.
"Great job to the Hammond Police on getting this sexual predator off the Region streets," McDermott added.
Nick Clegg has said that the Budget is one the biggest questions facing politicians at the moment and that: "compassionate Conservativism is dead or dying."
Speaking on The Agenda with Tom Bradby, the Deputy Prime Minister said:
Other guests on tonight’s programme are comedian Dom Joly, broadcaster and columnist Julia Hartley-Brewer and novelist Nikita Lalwani.
The Agenda with Tom Bradby to be broadcast on ITV at 10.35pm tonight.
The Greens have overtaken the Liberal Democrats in the latest poll from Tory peer Lord Ashcroft.
The survey put the Greens on a new high of 8%, just ahead of Nick Clegg's party on 7%.
The telephone poll of 1,000 adults gave Labour a three-point lead over the Tories, 31% to 28%, with Ukip on 18%.
Not all suspected paedophiles can be brought to justice, the head of the National Crime Agency (NCA) has admitted.
NCA director general Keith Bristow said it was "uncomfortable" to acknowledge that some of the 50,000 people who access indecent images of children online will not face prosecution.
Mr Bristow said: "I don't think I can be more candid than say, if there are 50,000 people involved in this particularly horrible type of criminality, I don't believe that all 50,000 will end up in the criminal justice system being brought to justice."
He argued the NCA's job was to "focus on the greatest risk and tackle those people".