Is capping domestic energy prices an equitable way to help the ‘just about managing’, or an electoral gimmick with a whiff of anti-free-market ideology? When it was Ed Miliband’s idea, it was certainly the latter. Now it’s likely to be included in Theresa May’s manifesto, offering a potential £100 saving for millions of homes on ‘standard variable tariffs’, it is defended by the ever-plausible Sir Michael Fallon as a matter of ‘intervening to make markets work better’.