Governments need positive headlines, and in these desperate times an industry-backed initiative to look at hydrogen-powered cars will do just fine. Mark Prisk, a very junior minister at the Department for Getting in the Way of Business, has launched an action plan (oh dear) with a pie-in-the-sky aim of producing a commercially viable technology by 2015.

Hydrogen-powered cars sound wonderful. Their only emission is water, probably pure enough to drink; even a badly-tuned hydrogen car won’t pollute the urban streets. Unfortunately, that’s the end of the advantages, and the list of drawbacks, from economic to thermodynamic, is dauntingly long.

Hydrogen must first be separated from water, putting the energy into it that is later extracted through the reverse process to drive the car. So it’s no more a source of energy than is a power line. Splitting the water molecule requires the highly organised, and expensive, energy from electricity, which must first be generated. Then the hydrogen must be transported in pressurised containers to specially adapted gas stations and pumped into pressurised containers in the cars.

At least Prisky’s exciting new initiative won’t cost us much. The £400 million earmarked for low-emission cars would run the state spending machine for about five hours. This is a hopeless venture. The money would be better spent on developing low-emission politicians instead.