A 29-year-old man was arrested and a number of items siezed during a raid on a house in Co Antrim by police officers investigating child pornography.
The house was raided this morning during simultaneous swoops by seven British police forces.
Eighteen addresses were raided across Britain as part of a five-month investigation by the Metropolitan Police's Clubs and Vice Obscene Publications and Internet Unit.
This morning's operation, codenamed 'Pilham', involved eight forces and focused on people using Internet groups and communities to distribute indecent images of children.
Police forces involved were the Police Service of Northern Ireland, Avon and Somerset, Grampian, Greater Manchester, Lincolnshire, Merseyside, and North Yorkshire.
Scotland Yard later said nine males, including a teenage boy, were arrested in London and the Home Counties as a result of the raids. They were all arrested on suspicion of distributing indecent images of children.