Red diesel is the single most misunderstood fuel in the transport industry. Almost everyone knows it is cheaper, plenty of people know someone who used to run something on it, and HMRC Notice 75 - the rulebook for rebated fuels - is the document that separates the folklore from the law. For a road haulage business the headline is short: your trucks run on full-duty white diesel, and rebated fuel is for a defined set of “excepted machines” doing defined work. But the details matter, because the penalties for getting it wrong run from lost fuel to a seized vehicle and, in serious cases, prison.
Red diesel is ordinary diesel carrying a reduced, or “rebated”, rate of excise duty, marked with a red dye so enforcement officers can spot it. The rebate exists so that fuel used for certain off-road and specialist purposes is not taxed like road fuel. Notice 75 treats references to red diesel as covering rebated diesel, biodiesel, diesel bioblend and hydrotreated vegetable oil alike. Kerosene is a heavy oil that can be fully rebated, but rebated kerosene is for generating heat in or on premises - it is not a vehicle fuel in any legitimate scenario.
Only vehicles and machines that qualify as “excepted machines” can use rebated fuel, and even they can only use it while doing qualifying work. The vehicle categories in Notice 75 are:
Anything not on that list cannot use rebated fuel at all. And being on the list is not enough on its own: the vehicle must also be doing a qualifying purpose at the time, such as agriculture, horticulture, aquatic farming or forestry. The purposes and the vehicle types interlock - not every purpose applies to every vehicle type.
The farm truck trap. Notice 75 is explicit: vehicles designed mainly for carrying goods, produce and implements are trucks. They are not agricultural vehicles even if what they carry is for, or results from, agricultural activity. A lorry hauling grain, fertiliser or livestock is a truck on white diesel, full stop. An agricultural vehicle qualifying under the notice must meet one of four specific definitions - for example a vehicle used only for agricultural purposes that is licensed for public roads only to pass between two areas of land occupied by the same person, under 1.5 kilometres by road - and it must be doing qualifying work.
The 2022 tightening. The rules were overhauled by the Finance Act 2022 and the Hydrocarbon Oil Duties regulations made that year, which stripped entitlement from most uses that previously qualified, including much construction and industrial use. If your understanding of red diesel comes from before 2022, it is out of date. “We have always done it this way” is the sentence HMRC hears most often and likes least.
The mixed fleet trap. A business running both qualifying machinery and ordinary trucks must keep the fuels rigorously separate. Notice 75 warns against mixing rebated fuel with other fuel in any tank or fuel system of a machine not allowed to use it, and HMRC may seize the fuel and the vehicle or machine if it happens.
The private land myth. There is no general “off-road” entitlement. Eligibility turns on the excepted machine categories in Schedule 1A to the Hydrocarbon Oil Duties Act, not on where the vehicle happens to be driving. A “public road” for these purposes is any road maintained at public expense - which includes footpaths and bridleways maintained that way.
HMRC officers can sample fuel, and if they cannot take a sample - because of an anti-theft device or a refusal - they may seize and remove the vehicle or machine until a sample can be obtained, with a penalty on top for the failure to comply.
For misuse itself, the notice is blunt: HMRC will seize any vehicle, vessel or machine using rebated fuel when it is not allowed to. Using rebated fuel wrongfully attracts a penalty under section 9(2)(a) of the Finance Act 1994, and the wider consequences scale up: the oil and any containers and equipment used in the offence can be seized, and a wrongdoing penalty can be imposed based on the extent of the illegal fuel use. In more serious cases involving assault, repeated offending or dishonesty, criminal action can follow, with an unlimited fine or up to seven years’ imprisonment, or both. Seized items come back, if at all, on restoration terms that HMRC sets - and its restoration and penalty decisions are appealable.
Red diesel saves real money for the farmers, rail operators and specialist machine owners it exists for. For hauliers it is a compliance risk with a short fuse: the dye does not wash out, the sampling is quick, and the penalties scale with the dishonesty.