The route is one of the longest in London, at around 15 miles (24 km) in length.

[2] The route was introduced in 1989 on a commercial basis by Metrobus and initially only had two return journeys per day Monday to Friday.

In 2014, it was taken over by Go-Ahead London who operate the route from Orpington bus garage.

[3] In October 2022, Irizar signed a contract with Go-Ahead London to supply twenty ie tram electric buses and the associated charging infrastructure for the route.

[4][5][6][7] The ie tram buses began operating on the route on 20 November 2024.