MILLIONS of motorists will start to see a new petrol standard being rolled out across most of the UK today.

But why is E10 petrol replacing the old E5 and will your car run the new standard?

When does it come into force?

Today across Scotland, Wales and England which means all cars that are eligible can start fuelling up with the new petrol. Although those in Northern Ireland will have to wait until next year.

What is it?

E10 is the new standard petrol grade. It contains more ethanol than the current E5 petrol, upping the ethanol content from 5% to 10%. This will see the UK fall into line with other European countries such as Germany, France and Belgium.

The UK Government says the change will apply to petrol only with diesel staying the same.

Why is it happening?

E10 is a greener fuel that will cut carbon dioxide (CO2) emissions in vehicles by blending more ethanol into the fuel.

The UK Government says this change is needed to meet climate targets, forecasting it could cut CO2 emissions by 750,000 tonnes a year – which equates to taking 350,000 cars off the road.

Will it work on my car?

Around 95% of petrol cars on the road are currently compatible with E10 petrol with most cars and motorcycles made after the 1990s are also compatible.

That leaves 5% which are not, meaning hundreds of thousands of cars across the UK, and thousands in Scotland will need to use the older E5 petrol.

If you’re unsure whether your car can use the new fuel then the Government has set up a website for motorists to check whether or not their cars are compatible with E10. Those unsure can visit:

If you can’t use the new E10, you will have to use the more expensive E5 which will still be available.

What if I put the wrong fuel in my car?

If your current car isn’t compatible with E10 and you accidentally fill it up with the new petrol you should be fine, but this shouldn’t be done regularly as it can damage these older vehicles over the long term.

If you top up on E10 with an incompatible car by mistake then you are advised to fill up your car with E5 as soon as you’ve used a third of the tank. This means mixing E5 and E10 shouldn’t cause any problems.

Is it really beneficial for the environment?

There hasn’t been widespread agreement over how green it is. Ethanol is made from plants, which absorb CO2 so the idea is that the CO2 emitted when the fuel is burnt will be offset.

But there is disagreement over whether both will cancel each other out.

Are there downsides to E10?

The main concern is that some in the motor industry argue that E10 is less efficient than E5, meaning motorists could get less mileage for their money.

The RAC says there are also reports that E10 is less stable, potentially meaning cars that have not been used in a while may have difficulty starting up.