This part of GOV.UK is being rebuilt – find out what beta means

HMRC internal manual

Hydrocarbon Oils Strategy

Tied Oils: law and regulations

The legislation is contained in the following:

Primary law Hydrocarbon Oil Duties Act 1979
Secondary law The Hydrocarbon Oil (Industrial Reliefs) Regulations 2002 (SI. 2002/1471)
Tertiary Notice 184A (para 5.5 in particular)