Last updated: 1 September 2026
Red diesel is not illegal in the UK. However, strict rules determine which vehicles, machines and activities are entitled to use it.
The rules changed significantly on 1 April 2022, when many businesses and industries lost their previous entitlement to use rebated diesel. Since then, whether you can legally use red diesel depends not simply on the type of vehicle or machinery you operate, but also what it is being used for.
HMRC refers to vehicles and machinery that qualify to use rebated fuel as “excepted machines”.
This guide explains the current UK red diesel rules, who can use it, where it can be used, the rules surrounding agriculture, construction, generators and marine use, and the possible penalties for using red diesel when you are not entitled to do so.
Important: Red diesel eligibility can depend on the precise vehicle, machine and activity involved. This guide summarises current HMRC guidance but should not be treated as individual tax or legal advice. If you are uncertain about a particular application, check the latest HMRC guidance before using rebated fuel.
Is red diesel illegal in the UK?
No.
Red diesel — also known as gas oil, marked diesel or rebated diesel — remains a perfectly legal fuel in the UK for qualifying uses.
It is essentially diesel supplied at a reduced rate of fuel duty and contains dyes and chemical markers that allow HMRC to distinguish it from fully duty-paid diesel.
The important legal distinction is where and how the fuel is used.
You cannot simply use red diesel because a vehicle or machine operates off-road. HMRC considers both:
- the type of vehicle, machine or appliance; and
- the purpose for which it is being used.
If the vehicle or machine does not qualify as an excepted machine for that particular use, red diesel must not be used.
This is why statements such as “red diesel is illegal” or “all off-road machinery can use red diesel” are both incorrect.
What changed to the red diesel law in April 2022?
Before April 2022, considerably more industries were entitled to use red diesel.
The government restricted that entitlement from 1 April 2022, meaning many commercial activities that had traditionally relied on red diesel had to switch to fully duty-paid white diesel or another suitable fuel.
Construction was one of the sectors most significantly affected.
However, the changes did not abolish red diesel.
Agriculture, horticulture, forestry and a number of other qualifying activities retained access to rebated fuel, alongside specific vehicles, machinery, marine uses and non-commercial applications.
As a result, eligibility today is based much more closely on the purpose for which the fuel is being used.
Who can legally use red diesel in 2026?
Current HMRC rules allow red diesel to be used in a number of specific circumstances.
The following provides a useful broad guide, but eligibility should always be checked against the precise use involved.
| Activity or application | Can red diesel be used? |
|---|---|
| Agriculture | Yes, for qualifying agricultural purposes |
| Horticulture | Yes, for qualifying purposes |
| Forestry | Yes, for qualifying purposes |
| Aquatic farming | Yes, for qualifying purposes |
| Arboriculture | Yes, for qualifying machines and activities |
| Rail transport | Yes, for qualifying rail vehicles |
| Ordinary commercial construction | Generally no |
| Road haulage | No for normal road-going vehicles |
| Golf courses and driving ranges | Yes, for qualifying uses |
| Community Amateur Sports Clubs | Yes, for qualifying uses |
| Travelling fairs and circuses | Yes, for qualifying machinery and activities |
| Commercial boats and marine transport | Generally yes |
| Private pleasure craft | Special rules apply |
| Commercial generators | Not automatically |
| Domestic/non-commercial heat and power generation | Potentially yes, subject to HMRC rules |
The critical point is that working in an eligible sector does not automatically make every machine or activity eligible.
Similarly, owning a tractor, excavator or other off-road machine does not itself give you the right to use red diesel.
Can farmers still use red diesel?
Yes.
Agriculture remains one of the principal permitted uses of red diesel.
Qualifying agricultural vehicles can use rebated diesel when carrying out activities relating to:
- agriculture;
- horticulture;
- aquatic farming; and
- forestry.
HMRC’s definition of an agricultural vehicle includes certain tractors, qualifying light off-road vehicles and specialist vehicles with permanently attached machinery used for agricultural, horticultural, aquatic-farming or forestry purposes.
Examples include machinery such as:
- combine harvesters;
- crop sprayers;
- forage harvesters;
- pea viners;
- mobile seed-cleaning machinery; and
- feed-milling machinery.
Agricultural vehicles can also use red diesel for some additional activities, including cutting verges, hedges or trees bordering public roads and dealing with frost, ice, snow or flooding.
There are detailed rules covering transportation, travelling between farms, servicing machinery and other activities, so businesses should check HMRC guidance where the use extends beyond straightforward agricultural work.
Can red diesel be used in construction machinery?
For ordinary commercial construction work, generally not.
The April 2022 changes removed the broad entitlement that previously allowed the construction industry to use red diesel in machinery such as excavators and other plant.
A machine being described as “plant” or being used off-road is therefore not enough to make it eligible for red diesel.
HMRC recognises certain categories of “special vehicles”, including:
- digging machines;
- mobile cranes;
- mobile pumping vehicles;
- works trucks; and
- road rollers.
However, these vehicles can only use red diesel when they are being used for specific qualifying purposes, such as activities relating to agriculture, horticulture, aquatic farming or forestry, or certain qualifying work on golf courses and Community Amateur Sports Club land.
A construction company carrying out normal building, civil engineering, groundworks or infrastructure work should therefore not assume that its plant can use red diesel simply because the machinery does not normally travel on public roads.
For most ordinary commercial construction applications, fully duty-paid white diesel or an appropriate alternative such as HVO will be required.
Can you use red diesel in a generator?
Sometimes — but not simply because the equipment is a generator.
Eligibility depends on what the generator is being used for.
Machines and appliances can use red diesel when they are used for certain qualifying purposes, including:
- agriculture;
- horticulture;
- aquatic farming;
- forestry;
- arboriculture;
- qualifying travelling fairs and circuses;
- golf courses;
- Community Amateur Sports Clubs; and
- generating electricity primarily for premises that are not used for commercial purposes.
HMRC defines “primarily” in this context as 75% or more of the electricity or heat generated being used for qualifying non-commercial premises.
Examples of premises HMRC considers non-commercial can include homes as well as certain public-sector, charitable and community premises.
A generator powering an ordinary commercial construction site, warehouse, factory or other profit-making business does not automatically qualify for red diesel.
Businesses using diesel generators should therefore establish the exact entitlement before purchasing or using rebated fuel.
Can red diesel be used for heating?
Red diesel can still be used for some heating applications, but the rules are considerably narrower than simply describing it as an “industrial heating fuel”.
Machines and appliances may use red diesel where they are generating heat primarily for premises that are not being used for commercial purposes.
HMRC regards at least 75% of the heat generated as needing to be used for the qualifying non-commercial premises for the “primarily” test to be met.
Kerosene is treated differently and can continue to benefit from its own rebated treatment when used for qualifying heating purposes.
Businesses looking for fuel for a commercial or industrial heating system should therefore check which fuel specification and duty treatment applies to their particular equipment rather than assuming red diesel is appropriate.
Can arborists and tree surgeons use red diesel?
There are specific allowances for arboriculture.
HMRC guidance confirms that machines and appliances other than vehicles that are used for forms of tree work can use red diesel.
Examples given by HMRC include:
- generators;
- woodchippers;
- stump grinders; and
- mobile elevating work platforms.
Rules for vehicles are different. A qualifying vehicle must meet the relevant vehicle category and usage requirements.
Agricultural vehicles may also use red diesel when cutting trees bordering public roads.
Can red diesel be used on a golf course?
Yes, for certain qualifying activities on an existing golf course or driving range.
This can include using appropriate vehicles or machinery to maintain the course and its facilities.
HMRC also allows qualifying use for activities such as repairing, renovating or adapting an existing golf course.
However, the entitlement does not simply extend to every activity taking place on golf-club land.
For example, HMRC specifically distinguishes maintenance of an existing golf facility from construction of a completely new golf course, driving range, clubhouse or other new structure.
Similar provisions apply to qualifying land maintained by a registered Community Amateur Sports Club (CASC).
Can you drive on a public road using red diesel?
In most circumstances, red diesel must not be used as ordinary road fuel.
However, the rule is more nuanced than saying red diesel can never be used on a public road.
Some qualifying agricultural and other excepted vehicles may legally travel on public roads while using red diesel when the journey itself forms part of an approved activity.
For example, qualifying agricultural vehicles may use red diesel when carrying out certain agricultural, horticultural or forestry work and when travelling to or from the location of qualifying work.
Agricultural vehicles may also use it when:
- cutting verges, hedges or trees bordering public roads; or
- dealing with frost, ice, snow or flooding.
There are separate restrictions covering unlicensed and SORN vehicles.
Red diesel must not be used simply to fuel an ordinary car, van, HGV or other road vehicle because it happens to spend some of its time off-road.
Can haulage companies use red diesel?
Normal road haulage does not qualify.
HGVs, delivery vehicles, vans and other normal road-going vehicles must use fully duty-paid road diesel where diesel fuel is required.
The fact that a vehicle may:
- enter a farm;
- visit construction sites;
- operate within a yard;
- transport agricultural goods; or
- spend some time away from public roads
does not automatically turn it into an agricultural or otherwise excepted vehicle.
HMRC specifically notes that vehicles designed mainly to carry goods, produce or implements are generally treated as trucks rather than agricultural vehicles, even when they are carrying agricultural goods.
Can boats use red diesel?
The marine rules differ from those applying to road vehicles.
HMRC states that boats and marine transport other than private pleasure craft are generally excepted machines and may use red diesel.
Private pleasure craft are subject to separate rules.
In Great Britain — England, Scotland and Wales — private pleasure craft can purchase red diesel, but users must declare the proportion being used for propulsion and pay the full rate of fuel duty on that amount.
Different rules apply in Northern Ireland.
Anyone purchasing red diesel for recreational marine use should therefore check the current private pleasure craft guidance rather than assuming the rules applying to commercial vessels also apply to them.
Can I switch a machine between red and white diesel?
Care is needed where machinery is used for both qualifying and non-qualifying work.
HMRC states that machinery containing rebated fuel should only be used for an entitled purpose.
Where machinery is hired out or switched between eligible and ineligible uses, the operator may need to:
- remove or flush the rebated fuel from the fuel system before the non-qualifying use; or
- use fully duty-paid diesel for all uses.
Simply switching the activity being carried out does not make red diesel in the tank legal for a non-qualifying use.
For businesses whose machinery regularly moves between different types of work, using fully duty-paid fuel throughout can sometimes avoid the compliance problems created by mixed qualifying and non-qualifying use.
What happens if you use red diesel illegally?
HMRC has powers to inspect, sample and test fuel held in:
- vehicles;
- machinery;
- vessels;
- appliances; and
- storage tanks.
If HMRC finds rebated fuel being used where it is not permitted, the consequences can be significant.
HMRC states that it may seize a vehicle, vessel, machine or appliance being operated with rebated fuel when that use is not allowed.
It can also seize fuel, containers and equipment associated with an offence.
In addition, offenders may be required to pay:
- the fuel duty that has been avoided, potentially going back up to four years; and
- a wrongdoing penalty based on the extent of the illegal fuel use.
In serious cases involving factors such as dishonesty, repeated offending or assault, criminal proceedings can result in an unlimited fine, imprisonment for up to seven years, or both.
For a more detailed explanation, see our guide to what happens if you get caught using red diesel.
Can HMRC test the fuel in your vehicle or machinery?
Yes.
HMRC officers have legal powers to inspect fuel and take samples to establish whether the correct fuel is being used.
They may inspect:
- fuel tanks;
- machinery;
- vehicles;
- storage tanks;
- vessels; and
- other equipment.
HMRC may also require owners or operators to make the fuel supply accessible for sampling and can request relevant documentation relating to the fuel.
Red diesel contains chemical markers as well as its distinctive dye, allowing HMRC to identify rebated fuel.
Interfering with fuel markers, refusing to permit a sample or obstructing an HMRC officer can itself lead to enforcement action.
What is the fuel duty on red diesel in 2026?
Red diesel is supplied at a lower fuel-duty rate than fully duty-paid white diesel.
As of 1 September 2026, the UK fuel duty rate on marked gas oil — red diesel — is:
6.48 pence per litre
This temporary rate took effect on 15 June 2026 and is currently scheduled to remain in place until 31 December 2026.
The main rate applying to diesel remains:
52.95 pence per litre
The government cancelled the fuel-duty increases previously planned for 1 September and 1 December 2026.
Fuel-duty rates can change as part of government fiscal policy, so businesses should always check the current rate when calculating future fuel costs.
For more detail on current rates, see our Red Diesel Tax Guide.
Why is red diesel cheaper than white diesel?
The primary tax difference is the reduced rate of fuel duty.
Red diesel is not a lower-quality version of diesel simply because it carries less duty. Fuel supplied as Class A2 gas oil is produced to the relevant specification for its intended applications.
The lower duty exists because its use is restricted to specific qualifying activities.
That is also why HMRC takes misuse seriously: using rebated fuel in a vehicle or machine that does not qualify means the full amount of fuel duty has not been paid.
For a detailed comparison of the two fuels, see our guide to red diesel vs white diesel.
Is HVO subject to the same red diesel rules?
Hydrotreated Vegetable Oil (HVO) is treated as heavy oil for fuel-duty purposes.
HMRC guidance allows HVO to be supplied at a rebated rate for the same qualifying uses as diesel, provided the relevant requirements are met and the fuel is appropriately marked and supplied.
However, renewable HVO is also widely supplied as a fully duty-paid fuel for commercial applications where red diesel is not permitted.
For businesses that lost their red diesel entitlement in 2022, fully duty-paid HVO can therefore be considered alongside white diesel where the equipment manufacturer approves its use.
What should I do if I am unsure whether I can use red diesel?
Do not rely simply on what your industry has traditionally used.
Ask:
- What type of vehicle or machine is it?
- What activity is it actually being used for?
- Does that combination qualify as an excepted machine under current HMRC rules?
If there is any uncertainty, check the current HMRC guidance before purchasing or using rebated fuel.
The rules can be highly specific, particularly where machinery performs several different roles.
Need a reliable red diesel supplier?
Compass Fuels supplies BS 2869 Class A2 red diesel to eligible customers throughout the UK.
From farms and agricultural contractors to other organisations with qualifying red-diesel requirements, we can arrange bulk deliveries from 500 to 36,000+ litres, with flexible delivery options available to suit your operation.
If you are unsure which fuel you need, speak to our team before ordering. We can discuss your fuel requirements and supply red diesel, white diesel, HVO and other commercial fuels to customers nationwide.
Request a red diesel quote or call Compass Fuels on 0330 128 9838.
Eligibility to use rebated fuel remains the responsibility of the fuel user. Where you are uncertain about your entitlement, refer to the latest HMRC guidance.
