I think what he says there is largely true. Like, as a Welshman, I want a ton of devolution to Wales, too, but I think that income tax and corporation tax are very dangerous things to devolve, particularly if you're left-wing. It probably starts with good intentions, like Scotland saying "hey, let's cut corporation tax to get businesses here and help Scottish unemployed", but businesses based in London probably won't move, so it mostly affects the North of England which is already pretty poor. The North retaliates, and realises they have to cut their corporation tax, and that affects the Midlands. The Midlands retaliates, and drop theirs, and you can see how it just devolves into a cycle of all the different devolved areas under a hypothetical federal scheme getting involved in a race to the bottom because each has an incentive to cut their tax slightly lower than the one next to them. The end result is a sort of prisoner's dilemma, because now they all have less money to do what they want and help the poorest in their region. I really want the regions to have basically complete control over their own spending, yes, but taxation is something that I feel should basically always be federal, lest Scotland seek prosperity by strip-mining the North or Wales.