The Northern Line Extension opened in September 2021 as a major extension to the London Underground network through the Vauxhall, Nine Elms and Battersea regeneration area, currently being transformed into a prestigious central residential and business district. It will act as a catalyst for growth within the city, helping to support 25,000 jobs and 20,000 new homes and providing a crucial link between new areas of development and existing residential areas within an inner-city district of south London.

It is home to the new American Embassy, the redeveloped New Covent Garden Market, the redeveloped Battersea Power Station and a new linear park.

The 3.2 km rail extension provides two new underground stations at Battersea Power Station and Nine Elms, a residential oversite development (OSD) at Nine Elms, two new ventilation shaft head houses in Kennington and new cross passages at Kennington Station.

The station designs focus on integrating into the surrounding local context, with prominent and welcoming entrances by both day and night. The internal environments are focused on passenger comfort and experience by creating intuitive routes for all passengers throughout the station, with architectural character provided through expression of engineering, natural and artificial light, integration of customer facilities and zoning of other services where practicable.

Cladding materials have been selected to be modular and/or prefabricated where possible, in order to improve constructability and quality and provide a calming and balanced but refined palette of materials, colours and textures between different elements.

Grimshaw has been working since 2014 as part of a contractor-led design and build consortium led by a Ferrovial Construction Laing O’Rourke joint venture (FLO) working for Transport for London (TfL) for this prestigious project and has been responsible for leading the architectural design from concept stage through to completion of construction (RIBA stages 2–5), with Mott MacDonald as multi-disciplinary lead consultant.