SE Trains Limited, trading as Southeastern, is a British train operating company owned by DfT OLR Holdings for the Department for Transport, that took over operating the South Eastern franchise in South East England from privately owned London & South Eastern Railway on 17 October 2021.

Cannon Street station, also known as London Cannon Street, is a central London railway terminus and connected London Underground station in Travelcard zone 1 located on Cannon Street in the City of London and managed by Network Rail. It is one of two London termini of the South Eastern Main Line, the other being Charing Cross, while the Underground station is on the Circle and District lines, between Monument and Mansion House. The station runs services by Southeastern, mostly catering for commuters in southeast London and Kent, with occasional services further into the latter.