In fact, rarely has an argument so confidently stated proved so awfully wrong. Far from efficient governance, it has produced decades of terrible outcomes in all the main policy areas for which the devolved bodies are responsible: health, education, local government and transport.
There is, however, a critical exception, because devolution has worked for one small section of the population: unimpressive politicians who, away from the glare of Westminster, are able to exert enormous power with little accountability. When their policies are questioned, we see a spectacle of frothing, self-righteous disdain, as happened this week in the Senedd.
Actual ability to run something is a rare skill. Expanding the number of politicians with access to power does not increase the number of such competent people. Thus devolution – or any other expansion of political control over life – leads to more incompetents attempting to exercise said power.
All this before we even start to talk about the inefficiency of political control, the lousy incentives and so on.