From the Wikipedia page [1] The N87 was a long-standing night-route with its origins as an all-night tram service. Introduced as route 287 after the withdrawal of the trams in 1952, it ran in both directions around a circular route in a figure of “8” from Victoria Embankment via Westminster, Kennington, Balham, Clapham, Tooting, Streatham, Brixton, Stockwell, Kennington, Elephant & Castle and Blackfriars back to Victoria Embankment. It was re-numbered N87 in 1960 in order to free up its original number for the new bus routes which were replacing the trolleybus services from the late 1950s.