It has been 49 long days since the Gorton and Denton by-election and there is no sign that the Green electoral wave is about to break. The surprise victory of Hannah Spencer, the plumber from greater Manchester, has done what last year’s Runcorn and Helsby by-election did for Reform UK: provide a populist insurgent with the momentum essential to its continued credibility. Next month’s local elections are likely to see this Green tide sweep through England’s town halls, particularly those in the capital. In hip Hackney Zack Polanski’s party hopes to win the mayoralty. It is also poised to make...