Lallands Peat Worrier neatly illustrates the madness of devolution premised on the imperative of maintaining established structures of power, privilege and patronage.
That the tax/benefit system should function, and be administered, as a coherent whole is a truth too obvious to be worth exploring. It stands to reason, therefore, that the very worst arrangement that might be envisaged is one in which the tax/benefit system is fragmented - with the devolved administration having partial and constrained control over only disparate bits of the system, while control of crucial aspects is retained by the central government.
If one were determined to find a way of making this situation even more fraught with the potential for conflict, confusion and catastrophic failure, then one would surely choose to divide control of the tax/benefit system between two governments operating in significantly different and increasingly divergent political cultures.
Such is the British establishment's 'solution' to the Scottish problem.
Were one so inclined by a healthy cynicism honed over many decades of observing the British political class in action, one might fancy there was a certain maliciousness underlying the evident ineptitude of the UK Government's latest round of constitutional tinkering.