London Bridge station in the context of "London Borough of Southwark"

The South Eastern Railway (SER) was a railway company in south-eastern England from 1836 until 1922. The company was formed to construct a route from London to Dover. Branch lines were later opened to Tunbridge Wells, Hastings, Canterbury and other places in Kent. The SER absorbed or leased other railways, some older than itself, including the London and Greenwich Railway and the Canterbury and Whitstable Railway. Most of the company's routes were in Kent, eastern Sussex and the London suburbs, with a long cross-country route from Redhill in Surrey to Reading, Berkshire.

Much of the company's early history saw attempts at expansion and feuding with its neighbours; the London Brighton and South Coast Railway (LBSCR) in the west and the London, Chatham and Dover Railway (LCDR) to the north-east. However, in 1899 the SER agreed with the LCDR to share operation of the two railways, work them as a single system (marketed as the South Eastern and Chatham Railway) and pool receipts: but it was not a full amalgamation. The SER and LCDR remained separate companies until becoming constituents of the Southern Railway on 1 January 1923.