Hard facts and informed opinion have been the first casualties of the maelstrom of comment, debate and public relations generated by the government’s plan to provide a subsidy of up to £5,000 to buyers of electric cars.

Missing is an answer to the main question: is this a good way of spending public money to address climate change? The government argues that the move will encourage early adopters of the technology, helping electric car manufacturers achieve economies of scale. But, given that it would cost more than £150bn to subsidise Britain’s entire car fleet, are there more cost-effective means of meeting our commitment to reduce UK carbon dioxide emissions to a fifth of 1990 levels by 2050?