Frequently Asked Questions on Red Diesel Fuel

If you plan on using red diesel (gas oil), you need to ensure you’re aware of the rules around its usage. The regulations are strict, so before you go ahead and use the fuel, it’s always a good idea to double check your individual usage with HMRC or Speedy Fuels.

Below is our easy to understand guide to using red diesel to help make things a little clearer. If you’d still like to speak with one of our team about using gas oil, call us today on 0330 123 3773.

What is red diesel fuel?

Red diesel (also known as gas oil, tractor diesel, cherry red and agricultural diesel) is a low-tax and therefore low-cost fuel that is widely used to operate registered off-road vehicles and permitted machinery. It can also be used to heat homes.

What vehicles can use red diesel after april 2022?

The rules around the use of red diesel in vehicles was changed in April 2022, restricting the use of red diesel in vehicles for:

  • Rail transport
  • Sailing, boating and marine transport (excluding private pleasure craft in Northern Ireland)
  • Agriculture, horticulture, fish farming and forestry

For more details about the latest rules on red diesel usage after April 2022, please read our updated red diesel rules guide for further information.

Do you need a licence to use red diesel?

No, you don’t need a licence to purchase red diesel; however, you must be an eligible user and you must sign an RDCO form upon purchase. You must only buy gas oil from a company who is HMRC registered. Read more about this on HMRC.

As of the 1st of April 2022, only users in the following sectors can use red diesel:

  • Travelling fairs and circuses
  • Fuel used for non-commercial purposes – electricity generation and heating
  • Agriculture, horticulture, fish farming and forestry
  • Rail transport
  • Community amateur sport clubs and golf courses
  • Sailing, boating and marine transport (excluding private pleasure craft in Northern Ireland)
When can i use red diesel?

The rules on red diesel are quite broad and depend entirely on what you’re using it for. We’ve provided details of the latest rules regarding red diesel usage which covers this information in more detail.

Is there an alternative to red diesel?

Yes, Speedy Flame (industrial heating oil) is a red diesel alternative that’s intended for commercial heating applications only. That’s because the heating oil is a zero VAT fuel.

If you’re looking for a clean burning alternative, you can switch to Speedy HVO fuel, our direct, drop-in diesel alternative that will reduce your net CO2 emissions by ca 90%.

Does red diesel have any other names?

Yes, red diesel is known by a number of other names such as gas oil, agricultural diesel, 35 seconds, cherry juice, tractor diesel, digger fuel and marine diesel.

Is red diesel red?

Yes – as its name suggests, gas oil contains a red dye with chemical markers in accordance with Customs and Excise requirements to enable HMRC or police officers to identify and quickly prosecute illegal usage. Upon testing, they must locate a marker dye or use dip testing.

Is red diesel exempt from tax?

No, red diesel isn’t completely exempt from tax. However, it is a heavily rebated fuel, so the tax charged is much less than on other fuels such as white diesel.

Can i use red diesel in a boiler to heat my home?

Whether you can run your boiler on red diesel depends on the model of your furnace. If your boiler is vertically conventionally fluid then you should be able to use the fuel to heat your home. However, this is a more expensive option than heating oil.

Can red diesel be used in cars?

Red diesel fuel is no different than regular white diesel; it has the same properties so it can power all diesel-powered engines. However, if you use red diesel in a road vehicle on public roads, it’s considered tax evasion and you will be breaking the law.

An exception to this is for farmers. They can travel up to 1.5km using red diesel in a car to access land on the public highway.

Can i use red diesel in a car on my farm?

You can use red diesel in a car on a farm, so long as it’s intended solely for off-road, farm-related use. You must not drive the car on the public roads if it’s powered on red diesel.

Will red diesel damage my car?

No, red diesel is exactly the same fuel as road diesel, except for the red dye added to it. All diesel-powered engines can use red diesel, although you will be breaking the law if you use it in road-going vehicles.

I’ve put red diesel in my car by accident, what can i do?

If you have put red diesel in a road vehicle by accident, then you should drain your tank of all the fuel as soon as you can. If you are unable to do this, then you should contact HMRC immediately and follow their instructions.

Are there any restrictions on using red diesel for agricultural contractors?

You can use red diesel as long as you are using it exclusively for farming, horticultural or forestry work. The automobile must also be listed for agriculture use.

Can you use red diesel in tractors for gritting roads?

Since 2012, agricultural vehicles (tractors, light agricultural vehicles and agricultural material handlers) can use red diesel on public roads to grit small roads in order to ensure safe travel for local communities.

Why does red diesel cost less than diesel?

Red diesel is a rebated fuel, which means it’s cheaper than road diesel (white diesel) as it has a significantly lower fuel tax levy required.

As red diesel is legal for use in sectors such as agriculture, horticulture and forestry, this makes it the perfect fuel to power vehicles in permitted industries that need low-cost fuel for work purposes.

Can you remove the red dye from red diesel?

While you can technically remove the red dye from gas oil, it’s actually illegal to do so – and traces of the dye will remain in the engine. The process to remove the red dye from the fuel is called fuel laundering and if found illegally doing so, you can end up with a prison sentence. It’s not worth the risk!

Can red diesel be traced?

Yes, the red dye is added to enable red diesel to be easily traceable for illegal use by police officers or HMRC.

What’s the fine for using red diesel illegally?

There isn’t a fixed fine, but if you’re found using it illegally, the HMRC will charge you for the restoration of your vehicle’s system to clean your tank and filters to remove the marker dye. You will be charged a fee for its removal. Your car can be detained, or you can even be back charged for the difference in cost between red diesel and road diesel over the time you’ve been using it.

Can red diesel be used as heating oil?

Yes, red diesel is commonly used for domestic heating applications. After the 1st of April 2022, red diesel can no longer be used as a commercial heating fuel. Our Speedy Flame industrial heating oil is a cost-effective alternative that has been specifically manufactured for boilers, dryers and furnaces.

Can red diesel be used in generators?

Red diesel can only be used in power generation for non-commercial purposes. For full details, please read our red diesel usage guide or call a member of our team on 0330 123 3773.

Can red diesel freeze in cold weather?

When the temperature drops, diesel fuel gelling can occur as it contains wax paraffins which usually improve fuel lubrication and viscosity. When it gets too cold, paraffin wax thickens and turns cloudy which can eventually clog filters and cause the fuel to no longer flow, rending your fuel inoperable. Learn more about red diesel and seasonality in our guide.

Can i carry two separate fuel tanks so i can switch between red and white diesel?

No, it is unlawful to transport two diesel cisterns that are equally able to be joined to the diesel engine.

How much does red diesel fuel cost?

Here at Speedy Fuels, we’re a family run business supplying red diesel to the building and farming industry. So if you’re looking for a consistent and expert company to cover your red diesel requirements, make certain we’re your main port of call. We provide competitive red diesel prices and nationwide deliveries to ensure you can keep your business running all year round.

Where can i buy red diesel from?

Speedy Fuels supplies businesses with red diesel across the country. Thanks to our widespread fuel depots and large number of tankers, 92% of our deliveries are made on the very next day.

What do i do with unwanted red diesel?

Leaving red diesel in a tank when it’s no longer in use can pose environmental hazards if left for a long period of time. However, removing it from your tank is highly dangerous if not done correctly. Speedy Fuels can come to your site and uplift any unwanted gas oil and potentially provide payment if it’s able to be recycled.

No matter whether you’ve found answers to the questions you’ve had about red diesel or not, or whether you’d like to learn more about how red diesel from Speedy Fuels can help benefit your business. Give our expert team a call today on 0330 123 3773 to discuss your requirements and learn more.