Anniversaries in May
- 1 May
- 1844 – London and Croydon Railway and South Eastern Railway open Bricklayers Arms station as an alternative terminus to London Bridge station.
- 1857 – North and South Western Junction Railway opens line from South Acton to Hammersmith & Chiswick.
- 1860 – Great Western Railway starts passenger services between Southall and Brentford Town.
- 1864 – Mid-Kent Railway opens the New Beckenham to Addiscombe Line.
- 1883 – District Railway extends from Acton Town to Hounslow Town.
- 1907 – Great Western Railway opens Denham to Uxbridge High Street branch line.
- 1939 – A collision between trains at Farringdon station injures 45.
- 1960 – Death of Charles Holden, architect of 55 Broadway and many London Underground stations.
- 1968 – British Rail closes the freight only Merton Abbey branch line.
- 1970 – The Port of London Authority closes its remaining dock railway system.
- 1979 – Jubilee line opens between Stanmore and Charing Cross taking over Bakerloo line services between Stanmore and Baker Street.
- 2 May
- There are no anniversaries today
- 3 May
- 1965 – South Acton to Hammersmith & Chiswick line permanently closes.
- 4 May
- 1936 – Metropolitan line extends from East Ham to Barking.
- 1942 – Great Western Railway ends passenger services between Southall and Brentford Town.
- 1971 – An out-of-service Northern line train runs into the end wall of the siding tunnel at Tooting Broadway killing the driver.
- 5 May
- 1930 – Amy Johnson takes-off from Croydon Airport at the start of her solo flight to Australia.
- 1947 – Central line extends from Stratford to Leytonstone.
- 6 May
- 1937 – Second Chelsea Bridge over the River Thames opens.
- 7 May
- 1945 – Formal end of use of tube stations as air raid shelters.
- 8 May
- 1962 – The last trolleybus service in London runs between Wimbledon and Fulwell depot.
- 1984 – The Thames Barrier across the River Thames is officially opened by the Queen.
- 9 May
- 1864 – A boiler explosion on an railway engine injures four people and damages Bishop's Road station.
- 1874 – Chelsea Embankment, part of Sir Joseph Bazelgette's Thames Embankment project, opens.
- 10 May
- 1812 – Birth of William Henry Barlow, railway engineer.
- 1847 – London, Brighton and South Coast Railway opens line from West Croydon to Epsom Town.
- 1886 – The London, Chatham and Dover Railway opens Blackfriars station.
- 1915 – Baker Street and Waterloo Railway extends from Queen's Park to Willesden Junction.
- 1927 – The body of Minnie Alice Bonati is discovered in five parts in a trunk at the cloakroom of Charing Cross station.
- 1984 – Gatwick Express services start operating between Victoria station and Gatwick Airport station.
- 2000 – Croydon Tramlink opens its first route between New Addington and Croydon.
- 11 May
- 1941 – Cannon Street station is bombed damaging an engine in the station.
- 12 May
- 1875 – Birth of Charles Holden, architect of 55 Broadway and many London Underground stations.
- 1907 – City and South London Railway extends from Angel to Euston.
- 1967 – Government announces plans to develop Stansted as London's third airport.
- 13 May
- 1983 – British Rail closes the Woodside to Selsdon Line.
- 14 May
- 1908 – Central London Railway extends from Shepherd's Bush to Wood Lane.
- 1999 – Jubilee line opens between Stratford and North Greenwich.
- 15 May
- 2009 – Construction of Crossrail begins.
- 16 May
- 1931 – The first London trolleybus services are run by London United Tramways.
- 1998 – Snow Hill tunnel reopens for passenger services.
- 17 May
- 1938 – District line train crash kills 6 when a train runs into the rear of another near Embankment station due to faulty wiring on a signal.
- 18 May
- 1941 – Northern line extends from Finchley Central to Mill Hill East.
- 1968 – British Rail closes Exhibition Station (Wembley) loop line and station.
- 19 May
- 1953 – Waterloo Air Terminal opens as a passenger terminal for coach transfers to Heathrow and Northolt Airports.
- 20 May
- 2018 – TfL Rail begins services between Paddington and Heathrow Terminal 4 as the second stage of the Crossrail service implementation.
- 21 May
- 1838 – London and South Western Railway opens from Nine Elms to Woking.
- 22 May
- 1865 – London, Brighton and South Coast Railway opens line from Sutton to Epsom Downs.
- 1897 – Blackwall Tunnel opens under the River Thames between Blackwall and the Greenwich Peninsula.
- 1954 – A road accident on a bridge near Farringdon station kills 3 when a lorry fails on to the railway tracks.
- 23 May
- 2000 – Croydon Tramlink opens its second route between Beckenham Junction and Croydon.
- 24 May
- 1282 – Edward I grants a Royal charter to the City of London to establish the Bridge House Estates to fund the upkeep of London Bridge.
- 1862 – Second Westminster Bridge over the River Thames opens.
- 1873 – Edgware, Highgate and London Railway extends from Highgate to Alexandra Palace.
- 1879 – Tolls to use Chelsea Bridge, Battersea Bridge and Albert Bridge to cross the River Thames are abolished.
- 2022 – Central tunnelled section of the Elizabeth line opens between Paddington and Abbey Wood.
- 25 May
- 1885 – Metropolitan Railway extends from Harrow-on-the-Hill to Pinner.
- 1900 – District Railway begins experimental electric train service between Earl's Court and High Street Kensington.
- 1933 – A passenger train derails at Raynes Park and is run into by another train killing five and injuring 35.
- 26 May
- 1135 – The Great Fire of 1135 destroys the wooden London Bridge.
- 1906 – Second Vauxhall Bridge over the River Thames opens.
- 1906 – London County Council opens Greenwich Power Station to supply electricity for its tramways.
- 27 May
- 1844 – West London Railway opens between Willesden Junction and the Kensington Canal near Addison Road.
- 28 May
- 1939 – Southern Railway opens line from Tolworth to Chessington South.
- 29 May
- 1854 – Second Paddington station opens as the replacement London terminus of the Great Western Railway.
- 1882 – South Eastern Railway opens line from Elmers End to Hayes.
- 1886 – Second Putney Bridge over the River Thames opens.
- 1938 – Southern Railway opens line from Motspur Park Junction to Tolworth.
- 2000 – Croydon Tramlink opens its third route between Elmers End and Wimbledon.
- 30 May
- 1870 – District Railway extends from Westminster to Blackfriars.
- 31 May
- 1915 – Metropolitan Railway completes "fast lines" between Kilburn and Willesden Green.
- 1934 – A crash of an Air France transport aircraft into a navigation beacon shortly after take-off from Croydon Airport kills 2.
- 1946 – Heathrow Airport opens as London's main Airport.
- 1948 – Central line extends from Newbury Park to Hainault.
- 1956 – The helicopter shuttle service between Waterloo Air Terminal and Heathrow Airport ends.
- 1997 – British Rail closes the Elmers End to Addiscombe Line.
- 2015 – TfL Rail begins services between Liverpool Street and Shenfield as the first stage of the Crossrail service implementation.
