[10] The Greater London Council formed a Docklands Joint Committee with the Boroughs of Greenwich, Lewisham, Newham, Southwark and Tower Hamlets in 1974 to undertake the redevelopment of the area.

A light railway system was envisaged, terminating either at Tower Hill tube station or at nearby Fenchurch Street, but both options were seen as too expensive.

Nonetheless, in 1976 another report proposed a conventional tube railway for the area and London Transport obtained Parliamentary powers to build a line from Charing Cross station to Fenchurch Street, Surrey Docks (now Surrey Quays railway station), the Isle of Dogs, North Greenwich and Custom House to Woolwich Arsenal.

[14] Two southern terminus options were put forward, at Cubitt Town (today's Island Gardens station) and Tiller Road, on the west side of Millwall Dock, with two possible routes to reach them.

The "central" option required the West India Docks to be infilled or bridged and would run down the middle of the peninsula, through what was at the time an area of derelict warehouses.

[15] Ultimately this latter option was chosen, though the 1981 London Transport report warned that without extensive development around Canary Wharf the area would be "very isolated with poor traffic prospects" – as indeed it was, for a number of years.

[21] In 1984, the contract for the initial system was awarded to a GEC / John Mowlem joint venture, which proposed fully automated operation using light rail vehicles.

[34][35] The initial system had a relatively low capacity, but the Docklands area very quickly developed into a major financial centre and employment zone, increasing traffic.

[37] Stations and trains were extended to two-unit length, and the system was expanded into the heart of the City of London to Bank through a tunnel, which opened in 1991 at a cost of £295 million.

[40] The east of Docklands needed better transport connections to encourage development, and a fourth branch, towards Beckton, was planned, with several route options available.

[41] A route from Poplar via Canning Town and the north side of the Royal Docks complex was chosen, and opened in March 1994 at a cost of £280 million.

[44] The ambitions of the operators were supported by politicians in Parliament, including the future Labour Deputy Prime Minister John Prescott, and Lord Whitty.

[46][47] It left the Island Gardens route south of the Crossharbour turn-back sidings, and dropped gently to Mudchute, where a street-level station replaced the high-level one on the former London & Blackwall Railway viaduct.

The line then entered a tunnel, following the route of the viaduct to a shallow subsurface station at Island Gardens, accessible by stairs or a lift.

[49] An extension to London City Airport from the existing Beckton branch was explored in the mid-90s, at first via travelator from Royal Albert, and then in 1998 via a proposed lift-bridge over the dock with an intermediate station at West Silvertown.

[53] On 2 December 2005, an eastward branch along the approximate route of the former Eastern Counties and Thames Junction Railway on the southern side of the Royal Docks complex opened from Canning Town to King George V via London City Airport.

[64] With the development of the eastern Docklands as part of the Thames Gateway initiative and London's staging of the 2012 Summer Olympics, several extensions and enhancements were undertaken.

[69] Elverson Road, Royal Albert, Gallions Reach and Cutty Sark have not been extended for three-car trains; such extension may be impossible in some cases.

When required, such as during engineering works or for special events, other routes may be operated, such as Beckton to Lewisham if the Bank and Tower Gateway branch is closed.

Alan Williams was appointed to produce the first temporary commission, called "Sidetrack", which portrays the ordinary and extraordinary sights, often unfamiliar to passengers, on the system and was displayed throughout the network.

[32][failed verification] There are no cabs because normal operations are automated; a small driver's console is concealed behind a locked panel at each end, from which the PSA can drive the car.

[95] In 2017, TfL opened bidding for new full-length, walk-through trains, subsequently awarded to CAF in 2019[96] and expected in service between 2024 and 2026,[87][97] following delivery and testing on the network of the initial units from January 2023.

TfL appointed Morgan Sindall to complete the work, alongside a £90m deal to build a new train shed and deliver further sidings.

The same technology is used by rapid transit systems including Vancouver's SkyTrain, Toronto's SRT, the San Francisco Municipal Railway and Hong Kong's MTR.

[120] In February 2024, TfL announced that KeolisAmey, ComfortDelGro and Connecting Docklands (a joint venture of AtkinsRéalis and Go-Ahead Group) had been shortlisted to bid for the next franchise.

[128] The Parliamentary Transport Select Committee favourably reviewed light rail in 2005,[129] and due to the success of the DLR, proposals for similar systems elsewhere emerged.

[130] The DLR has been successful, as have other recent light rail systems,[131] although it was earlier criticised for having been designed with insufficient capacity to meet the demand that quickly arose.

DLR cars, especially older rolling stock, were not designed with bicycles in mind – if they were allowed, they might obstruct doors and emergency exits.

[159][note 1] The extension to Dagenham Dock in East London, via the Barking Riverside development was first proposed in 2003,[160] and was anticipated that the project could be completed and open for use by 2017,[161] at a cost of around £750 million.

[162] In November 2008, the Mayor of London Boris Johnson announced that due to financial constraints the extension, along with a number of other transport projects, had been cancelled.