The Class 466 EMUs were built between 1993 and 1994 by Metro-Cammell in Washwood Heath, for the Network SouthEast sector of British Rail.

[6] Due to the units non-compliance with modern accessibility standards, since 1 January 2021 Class 466 units can only operate in multiple with Class 465s,[7] providing 6-car or 10-car suburban services out of Charing Cross, Cannon Street and Victoria mainline stations to various destinations in South East London and Kent.

A solid-state Auxiliary Converter provides 110 V DC and 240 V AC supplies; this is the source of the loud buzzing noise which can be heard when the train is stationary.

Some are scheduled to be replaced by Class 707s,[8] with two hauled to Worksop for store by Harry Needle Railroad Company in June 2021.

[9] The 466s were repainted by Wabtec Rail at Doncaster Works into a variation of Southeastern livery with lilac doors and midnight blue lower band.