London's tallest tower promises Europe's highest public viewing gallery

A new skyscraper, called 1 Undershaft, is set to become London's tallest tower, adding to the British capital's skyline.

Planned at 309.6 metres, 1 Undershaft will match The Shard as the tallest building in the UK.

Planned to be built between the ‘Gherkin’ and the Leadenhall building, the 74-storey office tower will be a key addition to the Square Mile’s future skyline.

The project, designed by Eric Parry Architects, received planning approval in December 2024.

The project involves demolishing the existing St Helen's Tower (118 meters) and is expected to begin construction soon, with completion slated for 2030.

1 Undershaft will be a 73-storey skyscraper featuring extensive public spaces, including a free-to-access elevated garden on the 11th floor, a public screen.

It will also hold Europe's highest public viewing gallery at the top, with the London Museum operating an education space on level 72.

It will provide high-quality, flexible office space, a new public square with a forest-inspired design, enhanced ground-level greening, and sustainable features like rainwater harvesting and solar panels.

The design also includes an innovative external bracing system that allows for uninterrupted floor plates, improving flexibility for tenants.

Among the tallest completed buildings in the City of London (the Square Mile) as of April 2025, 22 Bishopsgate is the tallest, standing at 278 metres.

Other notable tall buildings include the Heron Tower (230 metres with mast) and The Leadenhall Building (225 metres).

Currently, Europe’s current tallest is the Lakhta Center (462 meters | 1,516 feet) in Russia.

During construction, thousands of jobs are expected to build 1 Undershaft. Once completed, the building will house offices, luxury residences, and retail spaces.

The 1 Undershaft is expected to draw millions of visitors, especially to its observation deck for a unique city view.

Local businesses stand to gain from this wave of visitors. Environmental initiatives aim to reduce environmental harm, special during construction.

Undershaft's green credentials include features such as a BREAM rating, and the building itself aims to meet high environmental standards for the City of London.

The project's expected completion is in 2030, as per The Architects' Journal.
Urban planners call it “a prototype for future skyscrapers to be more environmentally conscious and integrated with their surroundings.”

The 1 Undershaft is set to be a landmark of innovation, part of the City of London's target of delivering a minimum of 1.2 million square metres of new office space, by 2040.