Green Illusions, a book by a California-based scholar, claims the process of manufacturing electric and part-electric cars is carbon-rich. Factor in the mining of rare-earth metals, used in batteries, and the book says electric vehicles are no better for the environment over their lifecycle than a conventionally-powered car. It simply moves the fuel usage to the point of manufacture.

We've yet to receive carmakers' viewpoints on this, but it'll be interesting to see how much the claims hold true. Toyota has already had to debunk two similar studies, with one famously pointing out that the Prius was worse on harmful lifetime emissions than a Hummer. Regardless of accuracy, it's the kind of headline-maker that tends to get repeated verbatim, which can be disastrous for an emerging sector.

It also makes you wonder if the author has missed the point. Assuming the figures are true, hybrid and electric vehicles still move harmful emissions out of city centres, which is good for urban air quality. And not all journeys can be carried out using public transport or person-power.