The new unleaded petrol which is set to be rolled out in a bid to reduce carbon emissions will not be compatible with some cars.
The E10 fuel will come into effect from September - but it is already being rolled out in certain forecourts.
This is the biggest change to forecourts since four star petrol was banned 20 years ago.
However some cars built before 2011 may be at risk of damage or even void insurance if drivers use the new petrol to fill their tanks.
This change is expected to affect almost a million cars across the country and you can double check if your car is affected, reports Birmingham Live.
There are a number of ways owners can check if their cars are affected by the change.
The Government's E10 checker will clarify if a vehicle is not compatible.
But drivers are being warned by the RAC that there will be makes of cars that will not be compatible with the E10 petrol and users should be made aware of them.
These are the 10 models that will have the most registered E10-incompatible cars in 2020, according to the RAC Foundation (number of cars in brackets):
1. Volkswagen Golf (28,066)
2. MG MGB (20,890)
3. Mazda MX-5 (18,162)
4. Nissan Micra (15,785)
5. Morris Minor (12,796)
6. Rover 25 (9,879)
7. MG MGF (9,352)
8. Ford Escort (8,947)
9. Rover Mini (7,614)
10. MG TF (7,568)
From September the standard, cheapest unleaded petrol must be a 10 percent bioethanol mix.
The existing E5 fuel sold at petrol stations currently contains five percent bioethanol.
Malcolm McKay, spokesman for the Historic and Classic Vehicle Association, said it was not all bad news as the E5 fuel would likely be available “for a while” due to the popularity for higher octane fuels.
He said: "It certainly hasn’t had as much publicity as the change from leaded to unleaded fuel.
"It's another of those things, I think that the classic car movement to an extent have been scared to make too much of a fuss.
"We’ve just got to find a way around it.
"E5 is still going to be available for a while but it's more a case of the Government has said it can be available.
"It’s then up to the oil companies and the suppliers to decide whether there is enough demand.
"But as it’s the higher octane fuel and there's quite a lot of younger cars that run a lot better and more efficiently on the higher octane fuel I think we will see it around for quite a long time."
