From September the government is changing the standard petrol that will be available from E5 to E10, and around 1 million vehicles in the UK are not compatible with the new fuel.
The government has said that E10 petrol contains up to 10% renewable ethanol, which is added to reduce CO2 emissions and help tackle climate change. Since 2011 all new cars sold in the UK have had to be E10 compatible.
The RAC has said the greener fuel could reduce CO2 emissions by 750,000 tonnes per year, the equivalent of taking up to 350,000 cars off the road.
The government also said E10 petrol is compatible with 95% of petrol-powered vehicles on the road today, including all cars built since 2011. E10 is already used around the world, including in Europe, the US and Australia.
There are around 32.7 million cars in the UK, with 18.7 million running on petrol. This means some 935,000 cars won't run properly on the new fuel.
There are also estimated to be 1.27 million motorbikes in the UK, almost all of which run on petrol, which means some 63,500 will be impacted.
Read more: Everything you need to know about E10 petrol
All drivers are advised to check if their car can use the new petrol on this government website. They will need to know the vehicle model to use the service and also the engine size and year it was manufactured.
The RAC said drivers should also contact car manufacturers with questions surrounding their specific vehicle. "As a rule, drivers of cars registered prior to 2002 are advised not to use E10 in their vehicle, as problems have been reported," it added.
It warned that, although an incompatible car will still run on E10 fuel, some parts may be damaged over longer periods as a result of bioethanol's corrosive properties.
One issue with E10 is that it is potentially less efficient and drivers may need to fill up more often. The RAC said there have been reports that E10 is a less stable fuel, which could make it more difficult to start a vehicle that has not been driven for an extended period.
If true, this would lead to drivers filling up more often, increasing the cost of their annual fuel bill.
One report has said almost all Ford cars sold in Europe since 1992 can run on E10, as can most Renaults sold since January 1 1997. Likewise, all Harley-Davidsons sold since 1980 should have no problems.
However, pre-2000 Citroens and Nissans may need to stick to E5.
E5 will still be sold at most petrol stations but it will be classified as "super" grade fuel, rather than the current "premium" grade, which means it will cost more.
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