A crucial railway line could be extending even further, transforming part of London.

       The London Underground network is split into lines, each serving different areas of the capital. The Bakerloo line at present only descends southwards until it reaches Elephant and Castle.

       However, Transport for London (TfL), the authority responsible for the Tube, has said it intends to build a proposed extension of the line to Lewisham.

       Now it has said that a project taking trains as far as the suburban area of Hayes in Bromley, southeast London, could be "built in parallel". Work could begin in the 2030s.

       In 2023, responding to a survey run by Bromley Liberal Democrats, less than half of respondents were satisfied with transport services in Bromley.

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       The party reported that the chief complaint from residents was a lack of connectivity with other services and with neighbouring boroughs (63%); the second most important issue being the need for improved reliability and frequency (46%).

       It had been previously confirmed that officials are aiming to run Underground trains past Elephant and Castle by 2040.

       The Mayor of London, Sadiq Khan, has said that new stock would be needed before the line is made longer, as the current carriages have been in use since the 1970s. The planned extension to Lewisham is reportedly thought to cost between ￡5.2billion and ￡8.7billion.

       An extension to Hayes could cost ￡10billion, Inside Croydon writes.

       TfL said: "We are considering extending the Bakerloo line to improve transport connections in southeast London and to enable growth in homes and jobs. An extension of the line to Lewisham via the Old Kent Road and New Cross Gate has been chosen as the best option to achieve those goals.

       "We are also considering a second phase of the extension beyond Lewisham to Hayes and Beckenham Junction. This would involve converting the National Rail line via Catford to Hayes to a London Underground operation."

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       The authority added: "The route would have a frequent Tube service, improving journey times for customers and offering better connections within southeast London, and into central London."

       Officials say that the current plan is to extend the Bakerloo line from Elephant and Castle to Lewisham, build a new Bakerloo line ticket hall at Elephant and Castle, and take the route from Elephant and Castle along the Old Kent Road where two new stations are proposed.

       Bosses also want to create a new station at New Cross Gate to provide better connectivity to National Rail, Overground and buses, and improve the interchange station at Lewisham linking National Rail, DLR and buses.