A CD protected with a digital watermark is being marketed via the Internet in Belgium - the high-tech watermark will prevent CDs being copied illegally. The first CD to carry the watermark will be one by Belgian singer SoulBob, which will be downloadable from the Internet.

While the download is underway, personal information including the name and address of the buyer will be added to the watermark.

Those copying CDs illegally will therefore be easy to track down.

The technology was developed in Germany and has already led to the catching out of several counterfeiters.