London Inner Ring Road

From the longer Wikipedia page

The London Inner Ring Road is a 12-mile (19 km) route formed from a number of major roads that encircle Central London.[1] The ring road forms the boundary of the London congestion charge zone, although the ring road itself is not part of the zone.

Starting at the northernmost point and moving clockwise, the roads defining the boundary are Pentonville Road, City Road, Old Street, Great Eastern Street, Commercial Street, Mansell Street, Tower Bridge, Tower Bridge Road, New Kent Road, the Elephant & Castle, Kennington Lane, the roads that constitute the Vauxhall one-way system and Vauxhall Bridge, Vauxhall Bridge Road, the roads that constitute the Victoria one-way system, Grosvenor Place, Park Lane, Edgware Road, Marylebone Road and Euston Road