Bakerloo line extension could add four Tube stops to South London by 2040

London's Underground network could gain new stations and connections over the next 15 years under plans to extend the Bakerloo line to Lewisham – but two stations once proposed for the Metropolitan line have effectively disappeared from the capital's transport ambitions.

Transport for London (TfL) is continuing to pursue its long-standing ambition to extend the Bakerloo line from Elephant and Castle to Lewisham, potentially transforming public transport connections through parts of South London that currently have limited access to the Underground.

Subject to securing the substantial funding required to deliver the scheme, construction could begin during the 2030s, with the extension potentially carrying its first passengers by 2040.

Current proposals would take Bakerloo line trains south-east from Elephant and Castle, creating new stations serving Burgess Park and Old Kent Road before connecting with existing rail infrastructure at New Cross Gate and Lewisham.

While that means two entirely new stations rather than four newly built ones, all four locations could effectively become new additions to the Underground network.

Taking the Tube into underserved communities

One of the biggest arguments for the extension is the opportunity to improve connectivity in areas of South London that have historically lacked direct Underground services.

Burgess Park, for example, currently sits some distance from the Tube network. Its nearest Underground options include Kennington and Oval on the Northern line, while South Bermondsey provides National Rail services to the east.

A new Bakerloo station would put the area directly onto London's Tube network for the first time.

The proposed Old Kent Road station would provide another new Underground connection before trains reached New Cross Gate.

New Cross Gate already serves London Overground and National Rail passengers, meaning its addition to the Bakerloo line could turn it into a considerably more important interchange.

At Lewisham, passengers would gain direct connections between the Underground, Docklands Light Railway and National Rail services.

The implications could extend beyond journey times.

Improved public transport is considered an important component of plans for new homes and regeneration along the extension corridor, potentially unlocking development in areas where transport capacity has previously been a constraint.

Could the Bakerloo go even further?

Lewisham may not necessarily represent the ultimate limit of the Bakerloo line.

There has long been discussion about eventually extending services further into South-East London, although those ambitions are considerably less developed than the Elephant and Castle-to-Lewisham proposal.

For now, TfL's immediate challenge is securing the funding necessary to turn the extension into a construction project.

With major transport infrastructure requiring long planning, approval and delivery periods, even a successful funding agreement would mean passengers waiting well into the next decade before seeing physical work begin.

The ambition nevertheless provides one of the clearest possibilities for a significant expansion of London's Underground network by 2040.

Two Tube stations that won't be built

While South London could gain new Underground connections, two proposed stations north-west of the capital have effectively been consigned to history.

Plans to extend the Metropolitan line into Hertfordshire through the Croxley Rail Link – later known as the Metropolitan Line Extension – have been abandoned.

The project would have diverted Metropolitan line trains away from the existing Watford Underground terminus and onto a former railway alignment towards Watford Junction.

Two new stations were planned.

The first, Cassiobridge, would have provided a new stop after the line branched away from the existing Metropolitan route.

A second station, Watford Vicarage Road, would have served the area around Watford FC's stadium before trains continued to the existing Watford High Street and Watford Junction stations.

At one stage, the extension was expected to be completed in 2020.

Instead, rising costs and funding problems saw the project suspended in 2017, and the proposed Underground extension is no longer being pursued.

Hertfordshire County Council is now considering alternative uses for the former railway alignment between Watford and Croxley.

For London's Underground, the contrasting fortunes of the two projects demonstrate how difficult expanding a mature urban railway can be.

The Metropolitan line proposals progressed for years before ultimately being abandoned. The Bakerloo extension still faces the crucial challenge of securing the money required to proceed.

But if TfL can overcome that hurdle, Burgess Park and Old Kent Road could gain completely new Tube stations, while New Cross Gate and Lewisham could appear on the Underground network – delivering one of London's most significant Tube expansions in decades.