WHILE sluggish electric vehicles remain a minority taste, their hybrid cousins are fast becoming the favourite mode of transport for politicians and environmentally conscious celebrities.
But they are not nearly as green as they claim to be, according to motoring experts. Staff at consumer magazine Which? have just completed a series of exhaustive tests on the latest hybrid models available in the UK with damning results.
They claim vehicles such as the Toyota Prius and new Honda Civic Hybrid perform little better than the equivalent-sized diesel-fuelled cars.
And they say some of the hybrid models are little more than clever marketing tools designed to ease the conscience of motorists looking to buy a large car.
The growing popularity of hybrid cars was thrown under the spotlight last week after Tory leader David Cameron posed beside a fully electric G-Wiz car. He later admitted to driving a Lexus GS450 hybrid.
George Marshall-Thornhill, a senior motoring researcher at Which? magazine, said: "Hybrid cars are still a novelty but politicians like Ken Livingston and David Cameron seem to love them.
"While they can be pretty good in town, they are lugging around a fairly heavy battery, so when the petrol engine is needed they become far less efficient.
"When you strip it right down, they are little better than diesel cars."
Most hybrids work by using an electric motor to run the car at low speeds of below 20mph, particularly when in urban areas.
But once the hybrid cars move on to open roads and go faster, the petrol engine takes over and also helps to recharge the battery. At speeds of around 70mph, both the petrol and electric engine work together.
The popularity of hybrid cars has grown in the last year as motorists have searched for ways to decrease their impact on the environment together with high-profile figures opting for the vehicles.
But new models such as Lexus's 4x4 RX400 hybrid have attracted intense criticism.
Marshall-Thornhill said: "There is some clever marketing going on here that offsets some of the guilt that goes with buying a large car such as a SUV [sports utility vehicle]."
Kevin Delaney, head of traffic and road safety for the RAC Foundation, believes hybrid cars are a necessary stepping stone to more environmentally sound vehicles.
He said: "Ideally we would have a diesel electric hybrid, which gives all the benefits of diesel and the benefits of a hybrid."