In Britain there is a higher rate of tax on normal diesel than off road diesel (red fuel), which makes red fuel cheaper.
During a random vehicle check near Hull in 1991 an officer discovered this fuel tank. It was divided into two sections; the smaller accessible tank held normal fuel. The larger concealed section of the tank, which had a hidden filling point, fed the engine with cheaper fuel.
The driver was ordered to pay back the tax he had avoided, and fined £10,000.
Criminal gangs are often behind the supply of this illegal fuel. The production and supply is a particular problem along the land boundary in Northern Ireland.
Lost revenue from oil fraud during 2004 amounted to £600 million.
In 2005-2006 1.5 million litres of illegal fuel were seized.