He wants England's biggest cities to become local hubs in order to decentralise government, a sort of regional devolution. Birmingham, Leeds, Manchester and the other core cities would have elected "metro mayors" able to set local income tax rates and so on. We, the people, have already rejected regional assemblies and elected mayors. Which part of "No" doesn't he understand?
It is quite easy to decentralise, all it needs is for Clegg and his chums in Westminster to stop being London centric with every damned thing. It certainly does not need another layer of government, quangos and advisers to achieve it.