Andy Burnham has promised “growth in every postcode”. It is a big, attractive political line – the sort of thing voters want to hear after years of feeling poorer, public services feeling stretched, and wages struggling to keep up with the cost of living. It is also a promise that tells us a lot about Burnham’s politics. He has long argued that Britain is too London-centric, that Whitehall is too slow, and that too many decisions about towns and cities are made by people who do not live in them.