Plans have been unveiled for a landmark £1bn skyscraper that is set to become the tallest building in the City of London and one of the most significant commercial developments in Europe.
Developed by Aroland Holdings, advised by Perennial Holdings, alongside Stanhope and Eric Parry Architects, the project known as One London will transform the City skyline with a striking new tower rising to 309.6 metres. Formerly known as 1 Undershaft, the development is expected to become London’s tallest skyscraper, the tallest office building in the UK and the joint-tallest building in Western Europe when completed in 2033.
Located at the prominent junction of Leadenhall Street and St Mary Axe, the development will deliver approximately 1.2 million sq ft of office-led accommodation at the heart of the capital’s financial district. Designed to meet the evolving needs of modern businesses, the tower will provide high-quality workspace while reinforcing the City’s position as a global centre for finance, technology and innovation.
The scheme received full planning approval from the City of London Corporation in December 2025, marking a major milestone for one of the capital’s most ambitious commercial projects. The development occupies a highly connected location, situated within a short walk of six London Underground lines and the Elizabeth line, offering exceptional accessibility for workers, visitors and businesses alike.
In addition to its transport connections, the site benefits from proximity to around 1,000 hospitality venues and 27 acres of public open space, helping to create a vibrant environment that supports both professional and social activity within the Square Mile.
Preparatory work is already progressing, with the deconstruction of the existing St Helen’s Tower now underway. The project team expects to appoint a main contractor later this year, with full construction anticipated to commence in 2028 following the completion of deconstruction and enabling works, as well as the finalisation of development financing arrangements.
Once complete, One London is expected to become one of the defining buildings of the next decade, joining the ranks of the capital’s most recognisable landmarks. Beyond its impressive scale, the development reflects the continued confidence in London’s commercial property market and the growing demand for premium, sustainable and future-focused office space in prime locations.
The project also highlights the ongoing evolution of the City of London, where new generations of workplace environments are being developed to accommodate changing occupier requirements, technological advancement and increasing expectations around sustainability, wellbeing and connectivity.
As construction moves closer, One London is poised to play a major role in shaping the future skyline of the capital, creating a new focal point for business, investment and architectural ambition in one of the world’s leading financial centres.
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