Running between Morden station and Camberwell Green, it is operated by Transport UK London Bus.

Route 45 was introduced on 1 October 1950 as a replacement for trolleybus route 34 between Battersea and Farringdon Street via Clapham Junction, Clapham Common, Stockwell, Brixton, Camberwell Green, Elephant & Castle and Blackfriars Bridge.

On 28 October 1978, the route was extended from King's Cross to Archway station.

[3] On 3 August 1985, route 45 was converted to one man operation with the AEC Routemasters replaced by Leyland Titans.

[12] In December 2024, it was confirmed that the changes would proceed with route 45 being restructured to operate between Morden station and Camberwell Green.