The 3.2km extension runs in tunnels from Kennington, through Nine Elms and to Battersea Power Station and is due to open in the autumn. Attention now shifts to completing new signalling software and fitting out the two new stations.

London's deputy mayor for transport Heidi Alexander said she is delighted that the scheme had reached this milestone. “Last year was one of the hardest in Transport for London's history so it's great to start 2021 on a positive footing, not least because the extension will support thousands of new jobs and homes for our city.”

Building a new arm of the Northern Line is the first major Tube extension since the Jubilee Line was extended east towards Stratford in the late 1990s. This latest project supports an urban regeneration programme around the former power station and promises to reduce journey times from Battersea to the City and West End to under 15 minutes.

Meanwhile to the east of the capital, Transport for London has started the next stage of technical work on a plan to extend the Docklands Light Railway towards Thamesmead to support 25,000 new homes and improve connectivity across the river. The extension from Gallions Reach would loop east towards a new station at Beckon Riverside before heading beneath the river.

Feasibility work will be carried out by TfL and a joint commission of Arup and Atkins for design, engineering and environmental assessment and with Aecom for socio-economic support. The extension will be funded by external partners through a £1M joint funding agreement between the London Borough of Newham, the Royal Borough of Greenwich and developers Thamesmead Waterfront, Aberdeen Standard Investments and St William.

“We know that public transport is key to helping unlock development in new areas,” said TfL's director of city planning Alex Williams. “By progressing work on the potential extension of the DLR to Thamesmead now we can ensure any future scheme is best placed to support the homes and jobs that London needs once funding is secured.”

(Photograph: Transport for London)