The findings are based on research by Transport & Environment, (Image: Getty)
Drivers buying plug-in hybrid cars in the belief they are cheaper to run are being misled, according to new research.
Owners can end up paying hundreds of pounds more a year than manufacturers’ official figures suggest – and potentially more than if running a petrol vehicle.
Research by the Energy and Climate Intelligence Unit (ECIU) has found that drivers of the UK’s best-selling plug-in hybrid electric vehicles (PHEVs) are likely to be spending almost twice as much on fuel as car makers claim – an extra £450 a year on average.
Based on manufacturers’ official fuel-efficiency claims, the top-selling plug-in hybrids should cost around £530 a year to run on petrol and electricity combined.
But when real-world driving is taken into account, annual fuel bills jump to £985, according to the analysis – largely because drivers end up using far more petrol than the glossy brochure figures suggest.
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The findings are based on research by Transport & Environment, which has found that plug-in hybrids consume 490% as much fuel as manufacturers claim.
The higher-than-expected fuel bills have a significant knock-on effect on the total cost of ownership of these vehicles, which includes purchase price, fuel, insurance, tax and servicing.
Over their lifetimes, the UK’s best-selling plug-in hybrids are found to cost £81 a year more to own and run than equivalent petrol cars. Compared with a similar fully electric vehicle, the difference is even starker, with plug-in hybrids costing almost £1,000 more each year overall.
The report comes after the Government’s decision in 2025 to weaken its Zero Emission Vehicle Mandate – a move critics say could encourage car makers to push more plug-in hybrids and fewer fully electric vehicles.
Changes to the policy allow manufacturers to meet sales targets through a mix of electric vehicles and lower-emission petrol and diesel cars.
Because plug-in hybrids are tested under conditions that produce impressively low official CO₂ figures, they offer an attractive way for manufacturers to hit emissions targets.
However, critics warn that those official figures bear little resemblance to how the cars are driven in the real world, meaning the targets can be met by selling vehicles whose actual emissions are not far off those of a conventional petrol car.
Colin Walker, transport analyst at the Energy and Climate Intelligence Unit, said: “This increasingly looks like a scandal with echoes of ‘dieselgate’. The industry’s successful lobbying of government will encourage the sale of hybrids and keep the nation’s driving bills high.
« Expanding the pool of hybrids on the road will leave the second hand market, where most of us buy our cars, awash with vehicles that are much more expensive to run and own than EVs. Some families will be left simply unable to make the switch to cheaper and cleaner electric driving.
“Drivers already pay a ‘petrol premium’ of hundreds, even thousands, of pounds year to run a petrol car rather than an EV, but it’s clear the premium to drive a plug-in hybrid is almost as high. Even with the introduction of a 3p a mile tax on EVs, they will remain cheaper to own and drive.
« But with the prospect of more families and businesses left paying more to drive hybrids than EVs, that’s a real knock to the nation’s productivity.
« We’re spending more to drive than we need to and so less in other parts of the economy.”
