This year, London's elected mayor and assembly turn twenty. But has London's mayoralty lived up to the expectations that were set for it? Have its three mayors been able to get to grips with the city's challenges? How have they responded to crises in the past - and what does the future hold?

The past two decades have seen three mayors with markedly different politics, outlooks and styles at the helm of the London government. And the role of the Greater London Authority has also been transformed through custom and practice, as well as statutory change.

At a time of tremendous uncertainty for the capital and the nation at large, this important new book marks the twentieth anniversary of London's mayor and assembly and investigates the relative successes and challenges of the mayoralty to date, before asking what comes next for London.

It combines analysis by experts with reflections from those closely involved in setting up, running and working with the Greater London Authority, alongside those who have held the position of Mayor of London themselves. In doing so, the book will draw useful lessons for the development of London government and devolved authorities elsewhere.