North Cheam tube station

The Northern line began life as an amalgamation of the City and South London Railway and Charing Cross, Euston and Hampstead Railway; the City and South London Railway opened in November 1890 running north from Stockwell,[1] and was extended in 1900 to Clapham Common[2] and in 1926 to Morden.[3] It might well have been extended to Sutton, via the then-unbuilt Wimbledon and Sutton Railway, however objections from Southern Railway that said route constituted an "invasion" of the territory allocated to them under the 1923 grouping of railways prevented Northern line trains from running any further south. Nonetheless, Morden remains the most southerly station on the network.[4]

In 1946, a report on London's railways to the Ministry of War Transport detailed possible new routes and rail lines for the London Underground, including the Victoria line and a route that would serve similar stations to Crossrail.[5] The same report recommended extending the Northern line to North Cheam, contingent on doubling the tracks between Kennington and Tooting Broadway such that Charing Cross trains would terminate at Tooting Broadway, and with an intermediate station at Morden South tube station. Both proposals would each have cost £1,500,000.[6] It would have occupied the site of what was then a Granada cinema on London Road in North Cheam, which was opened in 1937 and closed in 1969;[7] one half was demolished to make way for a community centre car park,[8] and the other half of which is now a Wetherspoon's.[7] However, as the doubling of tracks did not happen — by the report's own admission, "the period required for construction, under the most favourable conditions, would not be less than 30 years"[6] — the extension to North Cheam could not take place.[9]