 Complete the following phrase:  The Greater London Authority GLA, known colloquially as City Hall, is the devolved regional goverce body of the London region, which consists of the City of London and the ceremonial county of Greater London. It consists of two political branches: the executive Mayoralty currently led by Sadiq Khan and the 25-member London Assembly, which serves as a means of checks and balances on the former. Since May 2016, both branches have been under the control of the London Labour Party. The authority was established in 2000, following a 