|1843||Opening of the Thames Tunnel, constructed by Sir Marc Brunel and his son Isambard.|
||The Metropolitan Railway opened the world's first underground railway on 10 January between Paddington (Bishop's Road) and Farringdon Street.|
|1868||Opening of the first section of the Metropolitan District Railway from South Kensington to Westminster (now part of the District and Circle lines).|
|1869||First steam trains travel through the Brunels' Thames Tunnel.|
||Opening of the first Tube tunnel, from the Tower of London to Bermondsey.|
||Completion of what is now the Circle line.|
||The City and South London Railway opened the world's first deep-level electric railway on 18 December, from King William Street in the City of London, under the River Thames to Stockwell.|
||Prince of Wales opens the Central London Railway from Shepherd's Bush to Bank (the 'Twopenny Tube'). This is now part of the Central line.|
||Formation of the Underground Electric Railway Company of London (known as the Underground Group).|
Mergers brought all lines except the Metropolitan into the Group by the First World War.
||District and Circle lines electrified.|
||Baker Street & Waterloo Railway (now part of the Bakerloo line) opened from Baker Street to Kennington Road (now Lambeth North).|
Great Northern, Piccadilly & Brompton Railway (now part of the Piccadilly line) opened between Hammersmith and Finsbury Park.
||Charing Cross, Euston & Hampstead Railway (now part of the Northern line) opened from Charing Cross to Golders Green and Highgate (now Archway). Albert Stanley (later Lord Ashfield) was appointed general manager of the Underground Electric Railway Company of London Limited.|
||The Underground name first appeared on stations. Electric ticket-issuing machine introduced.|
First appearance of the famous circle and horizontal bar symbol (the roundel).
||First escalators installed, at Earl's Court station.|
||Last manually operated doors on Tube trains replaced by air-operated doors.|
||The Underground Group and the Metropolitan Railway become part of the London Passenger Transport Board, taking control of all the Capital's railway, bus, tram, trolleybus and coach services.|
||First Underground map in diagrammatic form, devised by Harry Beck.|
||From September, and until May 1945, Tube station platforms were used as air raid shelters. The Piccadilly line, Holborn - Aldwych branch, was closed and used to store British Museum treasures.|
||The London Passenger Transport Board was nationalised and became the London Transport Executive.|
||First aluminium train entered service on the District line.|
||End of steam and electric locomotive haulage of London Transport passenger trains.|
||The London Transport Executive became the London Transport Board, reporting directly to the Minister of Transport.|
|1969||The Queen opens the Victoria line.|
||The Underground and the Greater London area bus network passed to the London Transport Executive, reporting to Greater London Council.|
||Last steam shunting and freight locomotive withdrawn from service.|
The Victoria line extended to Brixton.
||Fatal accident on the Northern line at Moorgate in which forty-three people were killed.|
New safety measures introduced.
|1977||The Queen opens Heathrow Central station (Terminals 1, 2 and 3) on the Piccadilly line.|
|1979||The Prince of Wales opens the Jubilee line.|
||Brunel Engine House opens to the public: a museum about the birthplace of modern urban transportation, called by the Victorians the Eighth Wonder of the World, now an International Landmark Site.|
|1983||Dot matrix train destination indicators introduced on platforms.|
||London Regional Transport (LRT) created, reporting to the Secretary of State for Transport.|
||The Hammersmith & City and the Circle lines converted to one-person operation.|
||The Piccadilly line extended to serve Heathrow Terminal 4.|
||Tragic fire at King's Cross killed 31 people.|
||New safety and fire regulations introduced following the Fennell Report into the King's Cross fire.|
|1992||The London Underground Customer Charter launched.|
|1993||Angel Station reconstruction completed.|
Work started on the extended Jubilee line from Green Park to Stratford.
||Penalty fares introduced. London Underground took over the Waterloo & City line and responsibility for the stations on the Wimbledon branch of the District line from Putney Bridge to Wimbledon Park.|
Aldwych station and the Central line branch from Epping to Ongar closed.
|1999||London Underground restructured in preparation for Public Private Partnership.|
Shadow running to test working relations between London Underground and the infrastructure companies began.
||Opening of extended Jubilee line and through services from Stanmore to Stratford.|
||All 106 new trains in service on the Northern line.|
||Public Private Partnership (PPP) contract with Tube Lines for maintenance and upgrading of Jubilee, Northern and Piccadilly lines.|
||Oyster card introduced.|
PPP contracts with Metronet for maintenance and upgrading of Bakerloo, Central, and Victoria lines, and 'sub-surface' (Circle, District, East London, Hammersmith & City, Metropolitan) lines commence (April).
Tube transfers to become part of Transport for London (TfL) (July).
||52 people killed in bomb attacks on three Tube trains and a bus on 7 July.|
Tube carries one billion passengers in a year for the first time.
||Piccadilly line extension to Heathrow T5 opens.|
Metronet transfers to TfL control.
||Circle line changes shape. |
LU named Best Metro Europe.
||HM The Queen visits Aldgate station. |
LU achieves Carbon Trust Standard.
First ever air-conditioned, walk-through Underground train runs on Metropolitan line.
Tube Lines is acquired by TfL, marking the end of the PPP.
Last ever Chesham shuttle runs as through services take over.
||Passenger numbers exceed 1.1 billion for the first time during the 2010/11 financial year.|
Full fleet of brand new Victoria Line trains operational.
Green Park Station is first station within the Circle line to become step-free.
LU achieves PAS55 certification, the first UK railway operator to do so. LU also progressed to Level 3 of the Office of Government Commerce's P3M3 Maturity Model.