They have now been made safe, the NCA said, without giving further details. All the suspects were arrested for downloading or distributing child abuse images, but charges brought so far include serious sexual assault.
Britain has been rocked by a series of paedophile scandals in the past two years, since revelations that late BBC television host Jimmy Savile was a serial sex offender. The government recently launched a major inquiry into institutional abuse of children following allegations of a sex abuse ring involving senior politicians in the 1980s.
The NCA stressed that none of those arrested in the operation is a serving or former lawmaker or member of the government. Some 45 police forces across England, Scotland, Wales and Northern Ireland took part in the "unprecedented" operation, which involved searches of 833 properties and more than 9,000 computers, phones and hard drives. "This is the first time the UK has had the capability to coordinate a single targeted operation of this nature," said NCA deputy director general Phil Gormley.