Clapham Junction railway station is located at St John’s Hill in the south-west of Battersea in the London Borough of Wandsworth. It is not in Clapham but the area, influenced by the station, is commonly known as Clapham Junction. Many routes from London’s two busiest termini, Waterloo and Victoria funnel through Clapham Junction.

By number of trains passing through each day, some 2000 (most of which stop), it is the busiest railway station in Britain, and in Europe as signage of 17 June 2005 proclaimed. It is less busy by the number of passengers, most of whom pass straight through. Interchanges make some forty per cent of the activity and by that count too it is the busiest station in the UK.