Police in 14 countries across the world have carried out what has been described as the biggest ever operation to tackle child pornography.

In Germany alone, 93 properties were searched and about 2,200 people are now under investigation for the possession and dissemination of pornography.

The raids, which were co-ordinated by the German federal police, netted a mass of computer, video and documentary evidence.

As well as Germany, police in Switzerland, Austria, the Netherlands, Norway, France, Belgium, Denmark, Luxembourg, Portugal, Ireland the USA, Australia and Canada carried out raids.

In addition, 23 countries took measures to secure information from internet providers as evidence.

Operation Eye of the Needle was initiated after German police seized a computer belonging to a 41-year-old man last March. It contained around 16,000 pornographic images and 300 videos.

Data on the computer showed he had used the internet to swap and pass on the pictures within private groups. This allowed police to identify other people who were holding pornographic material.

They hope that the evidence amassed in Wednesday's raid will lead them to even more suspects.

Large amounts of data have been passed on to the US Customs' Cybersmuggling Center - a special department dedicated to dealing with child pornography.

German police have said that the operation proves that with multinational co-operation it is possible to combat child pornography on the internet.

Differences between national legislations and the anonymity afforded by the internet have in the past made it difficult to combat successfully the spread of pornography.