Panorama goes undercover in Britain's seven-billion-pound security industry, revealing that a highly organised illegal element still operates in the industry that runs everything from CCTV cameras in our cities to bouncers in our pubs and guards at our hospitals. With testimony from a well-placed whistleblower, it asks whether the body set up to clean up the industry is succeeding, and exposes the loophole that allows criminals to remain and flourish within it.