Britain's petrol and diesel is among the most expensive in Europe. But the rising cost of fuel has also placed it at the heart of a growing criminal black market. High value, untraceable and in constant demand, fuel has become the perfect illicit commodity. It is a crime that stretches from drivers filling up at garage forecourts without paying, to a dark and dangerous underworld run by gangsters and former terrorists. With exclusive access to the police and HM Revenue and Customs teams tasked with fighting fuel crime, Panorama reporter Samantha Poling investigates this multi-million pound illegal business.