Greater London Authority

The Greater London Authority (GLA), colloquially known by the metonym City Hall, is the devolved regional governance body of Greater London, in the United Kingdom. It consists of two political branches: an executive Mayor and the 25-member London Assembly, which serves as a means of checks and balances on the Mayor. The authority was established in 2000, following a local referendum, and derives most of its powers from the Greater London Authority Act 1999 and the Greater London Authority Act 2007.