The Common Serjeant of London is an ancient British legal office, first recorded in 1291, and is the second most senior permanent judge of the Central Criminal Court after the Recorder of London, acting as deputy to that office, and sitting as a judge in the trial of criminal offences.

The Central Criminal Court of England and Wales, commonly referred to as the Old Bailey after the street on which it stands, is a criminal court building in central London, one of several that house the Crown Court of England and Wales. The street outside follows the route of the ancient wall around the City of London, which was part of the fortification's bailey, hence the metonymic name.