A National Health Service prescription form is supposed to provide the sick with free medicine, but in the hands of crooked doctors and chemists it has become the key to a multi-million pound fraud.

Tonight's programme exposes the rackets undermining the prescription of medicines and spectacles. It also documents how the NHS is fighting back by using its special investigators in an attempt to smash British-based fraud rings and tackle the growing interest in prescription frauds being shown by organised crime overseas.

(Note: as Panorama is topical and likely to react to events in the news, the above programme is liable to change.)