
London Underground is on the brink of one of its biggest changes since it was opened in 1863.

Part of its winding network is poised for 24-hour operation this autumn sparking debate and strikes from Tube workers.

As negotiations continue, MailOnline Travel looks back at fascinating archive pictures from the Underground's humble beginnings.

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A London Underground official drinking a cup of coffee during trials of new automatic trains on a section of the Central Line

A traveller buys a London Underground season ticket from a vending machine at Highgate Station in London

Not entirely happy: A man writing on a complaints poster on the London Underground

Relax while you wait: Members of the public being entertained by an ENSA concert party in Aldwych Underground Station in 1940

In a bid to solve the problems of increased traffic congestion, a 1855 Act of Parliament was passed giving a green light to the construction of an underground rail network between Paddington and Farringdon Street via King’s Cross.

This pioneering service was to be named the Metropolitan Railway.

Its debut was in 1863 and the following year the Hammersmith and City Railway also opened.

The underground railways rapidly expanded and eventually incorporated New Cross on the East London Railway and Whitechapel and Hounslow and Wimbledon on the District.

Now the network had expanded onto 11 lines.

Customers using the new telephones in the modernised ticket hall at Oxford Circus underground station in September 1968

Familiar scenes: A strike on the London Underground causes huge queues to build up at the bus stops outside London's Liverpool Street Station in September 1939

Sparkling: A brand new tube train makes one of its first journeys on the London Underground in 1960

Morning commute: City gents travelling by the London Underground railway system in 1939

Carrying 1.2 billion passengers a year and serving 270 stations, it links central London to Surrey, Kent, Essex, Hertfordshire, Middlesex and Buckinghamshire.

During the morning rush hour London’s busiest Tube station is Waterloo, with over 57,000 people entering during the three-hour peak.

The busiest station in terms of passengers each year is Oxford Circus, used by around 98 million passengers in 2014.

The entire network adds up to 249 miles, 45 per cent of which is in tunnels and 114,500 miles is travelled by each Tube train each year.

Parts of the Jubilee line reach down to 105ft below sea level, while the Northern line dives down 221ft.

A platform of the Central London Railway extension at Liverpool Street Station in July 1912

Traffic and pedestrians bustle around Bank Underground Station in Throgmorton Street circa 1895. The Bank of England can be seen on the left

A TIMELINE OF THE TUBE'S INCREDIBLE JOURNEY Old-fashioned: The interior of an all-steel London underground train is pictured around 1920 1863: London's underground Metropolitan or Met welcomes its first passengers. Within a month it would be welcoming 26,000 passengers a day. 1869: The East London Railway starts running steam trains through the Thames Tunnel. Built by Marc Brunel and his son Isambard Kingdom Brunel, it was originally opened as a foot tunnel in 1843 for pedestrians to travel under the river between Rotherhithe and Wapping. It now forms part of the London Overground railway network. 1884: The Inner Circle line (now part of the Circle line) is completed through linking up the Metropolitan and District lines at both ends. 1890: The world’s first deep level electric tube railway is opened between Stockwell and King William Street (now mostly part of the Northern line). Access to the station platforms was by hydraulic lift. The Underground first becomes known as the Tube. 1905: The District and Circle Lines become the first to become electrified 1908: The Underground name and the iconic round symbol with a flat horizontal bar through it appear for the first time. 1911: The first escalators are turned on at Earl's Court station. 1929: Manual doors are used on the Underground for the last time with air operated doors used for the first time. 1933: The first Underground map in its recognisable modern form is produced by Harry Beck. The devastating Kings Cross fire in 1987 saw 31 people killed The devastating Kings Cross fire in 1987 saw 31 people killed Familiar: A passenger points out Piccadilly Circus on an early Underground map. The modern graphic design of the maps was first drawn up by Harry Beck in 1933 1940: The Underground played a key role in the Second World War, stations being used for the first time as shelters during the Blitz and a stretch of the Picadilly Line used to store treasures from the British Museum 1952: The first aluminium trains are introduced. 1969: Queen Elizabeth II takes the controls of a train as she opens the Victoria Line 1971: The last steam shuntings and freight locomotives use the Underground. 1975: 43 people are killed in a train crash on the Northern Line at Moorgate. 1987: A fire at Kings Cross station kills 31 people. 1994: Penalty fares are introduced on the Underground for the first time. 2003: Oyster cards are introduced for passengers and busking at Underground stations is legalised. 2005: 52 people are killed in bomb attacks on three Underground trains and a London bus on July 7. 2007: The Underground carries one billion passengers in a year for the very first time. Advertisement

Refurb: A 'new-look' London Underground station in 1960 with its long escalators

October 1919: Tottenham Court Road at the junction with Oxford Street and Charing Cross Road, London. The Court Playhouse is on the right, and the Underground station in front

Hammersmith Broadway with the underground station on the right and elaborate railings at the entrance to public conveniences in the centre, in 1910