Could devolving more power to Britain’s cities and regions help to stem a tide of political disaffection? Earlier this year, the U.K. took significant steps to grant more direct control to its regions by giving six metro areas—including Manchester and Liverpool—their first ever directly elected mayors, joining London whose mayorship was established in 2000 and breaking with British political tradition.

Still in their infancy, these offices are developing in a climate where regional British voters…