The Guildhall is a building in the City of London, off Gresham and Basinghall streets, in the wards of Bassishaw and Cheap. It has been used as a town hall for several hundred years, and is still the ceremonial and administrative centre of the City of London and its Corporation. The term Guildhall refers both to the whole building and to its main room, which is a medieval-style great hall. The Guildhall complex houses the offices of the City of London Corporation and various public facilities.
The City of London website page on the Guildhall is [1] and the Wikipedia page is [2].