Twenty-four men have been arrested in Sussex on suspicion of having or sharing indecent images of children, as part of an unprecedented national crackdown.

Thirteen children in Sussex have been referred to children’s social services following the arrests co-ordinated by the National Crime Agency (NCA), although police stress there has been no evidence of any specific risk.

The NCA spoke about Operation Notarise for the first time today, saying it had kept quiet until now to protect children and secure evidence.

Investigators are examining 332 computers and related items seized in Sussex, plus books, magazines, DVDs and cassettes. All those arrested here, ranging in age from their twenties to sixties, are on bail.

Assistant Chief Constable Stuart Cundy, of the Surrey and Sussex Specialist Crime Command, said: “Those who access indecent images should know the internet is not anonymous and we will pursue you.”

The National Crime Agency handed 46 files to Surrey and Sussex paedophile on-line investigation teams, sparking the arrests from April to June, including seven in Surrey.

None of those arrested in Sussex had unsupervised access to children during their work, a Sussex police spokesman said. Across the U.K., 660 people have been arrested under the operation, 39 of whom were registered sex offenders.

They include doctors, teachers, former police officers, Scout leaders and care workers, a National Crime Agency spokesman said. Their charges so far range from possessing indecent images of children to serious sexual assault, although most are still on bail.

NCA Deputy Director General Phil Gormley said he aimed to prevent offending. He said: “A child is victimised not only when they are abused and an image is taken. They are re-victimised every time that image is viewed by someone.

“Some of the people who start by accessing indecent images online go on to abuse children directly.

“So the operation is not only about catching people who have already offended – it is about influencing potential offenders before they cross that line.

“We want those offenders to know that the internet is not a safe anonymous space for accessing indecent images, that they leave a digital footprint, and that law enforcement will find it.”