Anyone familiar with Centre for Cities' work will know we have long supported city devolution. We strongly believe that taking political decision-making out of Whitehall and giving more powers to cities is good for democracy and national and local economies.

But we're also clear devolution is a means to an end. Its success isn't measured by how many powers and responsibilities are handed over. Success is whether these new powers, and the powers they already have, are used to improve citizens' lives.