Three computers were seized for analysis in south Oxfordshire during a national police crackdown on child pornography being peddled on the Internet.

Officers taking part in Operation Magenta executed a total of 75 warrants nationwide, including three in west Oxfordshire.

Police are refusing to disclose where the raids took place in a bid to prevent action from vigilantes. A total of 17 officers were involved in the operation in south Oxfordshire and were mainly from CID and the Child Protection and Sexual Crime Unit. No arrests were made.

Thames Valley Police spokesman Paul Anthem said: "Officers searched three addresses and seized various property. This will now be sent for analysis.

"We have liaised closely with colleagues from Hertfordshire Constabulary and Greater Manchester Police. "Thames Valley officers in Force Intelligence and Area Intelligence have been carrying out investigations prior to these warrants being executed. These inquiries are continuing."

A total of 35 police forces took part in yesterday's raids, executing warrants from 6am. The operation is the largest of its kind ever to be undertaken in the UK.