As the UK moves towards more sustainable and efficient motoring options, the likelihood of car buyers of purchasing a hybrid is growing, but how fuel efficient are they?

Well according to a report by consumer affairs magazine, Which? there are eye-opening findings on the real fuel costs for those who opt to go with a PHEV.

The watchdog analysed the performance of 22 popular plug-in hybrids and found that the bold claims of many manufacturers might not be what they seem. The worst performer in the Which? test was the BMW X5 plug-in hybrid which was shown to be 72 per cent less efficient than published figures - a difference which would cost the owner £669 extra a year. The report found that the BWM could only achieve 52.8 miles per gallon, compared to the claim of 188.3 miles per gallon.

“A fuel-efficient plug-in hybrid vehicle is an attractive feature for prospective buyers, as many will expect to spend less on fuel and reduce their carbon footprint,” said Natalie Hitchins, Head of Home Products and Services for Which? “Yet our research shows many hybrid models are not as efficient as the manufacturers claim, which means motorists could be spending more on fuel than they anticipated.

“It is clear that the standard set for calculating fuel consumption is flawed and should be reviewed to better reflect real-life driving conditions. This would ensure manufacturers advertise more accurate figures and consumers have a better understanding of how much they should expect to spend on fuel.”

BMW also performed poorly with their 2 Series Active Tourer, which was 71 per cent less efficient. The Mercedes B-Class plug-in hybrid (67 per cent less efficient) was also highlighted.

At the other end of the scale the Toyota Prius performed best, even though it was 39 per cent less fuel-efficient than official figures.

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