Local government in London recent organisation, having been set up in 2000 to replace the similar Greater London Council (GLC) which had been abolished in 1986. The headquarters of the GLA and the Mayor of London is at City Hall. The current Mayor of London is Sadiq Khan who was elected in 2016, replacing Boris Johnson, who served two terms. Health services in London are managed by the national government through the National Health Service, which is controlled and administered in London by a single NHS Strategic Health Authority called "NHS London". The 33 local authorities are the 32 London borough councils and the
Lord Mayor of London been mandatory for election to the Lord Mayoralty. Two Sheriffs are selected annually by Common Hall, which meets on Midsummer's Day for this purpose. By an ordinance of 1435, the Lord Mayor must be chosen from amongst the Aldermen of the City of London. Those on the electoral roll of each of the City's 25 Wards select one Alderman, who formerly held office for life or until resignation. Now each Alderman must submit for re-election at least once in every six years. The Lord Mayor is then sworn in November, on the day before the Lord Mayor's Show ("see below").