A new eco-friendly petrol is going to begin arriving at station forecourts this month but a quarter of drivers still don't understand if they can use it, claims the RAC.

E10 is to begin replacing E5 as the standard grade of petrol in the UK because it is kinder to the environment.

But an estimated 27% of motorists have not yet checked with their car is compatible with the new fuel, warns the motoring organisation.

All vehicles produced since 2011 have been made to accept the new E10 grade, which it is hoped will contribute to UK efforts to tackle the problems of climate change and meet emissions targets. However an estimated 600,000 vehicles on our roads may not be suited to having E10 in their tanks.

This includes classic cars, or what the government also refers to as 'cherished' and older vehicles, some models of moped particularly those with an engine size of 50cc or under and some specific makes and models of car from the early 2000s are among those which may find they are not able to take the new petrol on board.

The RAC is encouraging all drivers to now double check their vehicle's compatibility with the new mix of petrol via a free official online checker as the roll out begins.

Those with incompatible vehicles – which could be hundreds of thousands of drivers – will have to seek out and pay for more expensive, E5 super unleaded if they wish to keep them running. A litre of super unleaded is likely to cost around 12p more per litre than standard unleaded at the pumps, a move which could impact many lower income households who are often driving older cars.

Howard Cox at FairFuel UK talking about the changes

There is also a warning that the changes could also impact the resale value of certain vehicles if they now come with the need to then use the more expensive fuel.

The new E10 petrol contains up to 10% bioethanol, replacing E5 which has up to 5%, and so will help to cut carbon dioxide emissions. But anyone tempted to fill up their non-compatible car with £10 petrol in an attempt to save money could find it causes damage to seals, plastics and metals over a lperiod of time because bioethanol has corrosive properties.

RAC head of policy Nicholas Lyes said: “E10 petrol has already started appearing on forecourts to replace the old E5 blend, and that process will continue at pace in the coming weeks.

“But while the vast majority of drivers of petrol cars aren’t affected, a sizeable minority will be and the only way to be sure is to use the official online checker. Those that discover their cars aren’t compatible will unfortunately need to seek out and pay for a hefty premium for E5 super unleaded fuel instead.

"The cost of doing this could quickly add up for people who need to use their cars regularly, something our research shows all too plainly. Drivers who will continue to rely on E5 will also need to make sure the filling station their visiting stocks the fuel in the first place, or risk running out of fuel and having to call on their breakdown provider.

“We’d also like to remind owners of classic cars that need to be careful not to accidentally top up with E10 and then leave it sat unused in the tank for long periods, something which can lead to expensive damaged plastics, metals and seals.”

To learn more about E10 petrol and to check your car's suitability click here.

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