Aroland Holdings advised by Perennial Holdings, Stanhope and Eric Parry Architects have unveiled plans for One London, which would be the City of London's tallest tower, as well as the tallest office space and joint-tallest building in Western Europe on completion in 2033.
The development would rise to 309.6 metres and provide 1.2 million square feet of office-led space.
Stanhope was picked in 2022 to oversee revisions to the redevelopment of 1 Undershaft, the site of the St Helen’s building, also known as the Aviva Tower, in the centre of the financial district.
CoStar News revealed in 2023 that consultation had begun on plans for a 74-storey tower that would soar above the current tallest building in the City, 22 Bishopsgate, and be the same height as Western Europe's tallest building, The Shard, in London Bridge on the other side of the river.
In November 2016, the City of London Corporation granted consent for the existing building to be replaced with a 73-storey commercial development, comprising 1.4 million square feet of predominantly office space.
Formerly known as 1 Undershaft, the latest iteration, One London, secured full planning consent from the City of London Corporation in December 2025. It sits at the junction of Leadenhall Street and St Mary Axe, within a six-minute walk of six Underground lines, the Elizabeth line, around 1,000 hospitality venues and 27 acres of public open space. Deconstruction of the existing building, St Helen’s Tower, is underway, with a main contractor appointment expected later this year. Construction is planned to start in 2028 after the completion of deconstruction and enabling works and securing development financing.
One London's office floorplates range from 12,000 to 26,000 square feet. Each floor has a three-metre floor-to-ceiling height. There is 230,000 square feet of amenity with 125,000 square feet freely accessible to the public. The scheme also proposes 109,000 square feet of new landscaped gardens and terraces across multiple levels, with 68 trees planted at ground and podium levels.
At the top of the tower, Level 73 will house Europe's highest publicly accessible viewing gallery at just over 300 metres which will be operated by London Museum. On Level 72, London Museum will operate education space focused on the city's history and geography. At Level 11, there will be a free-to-access elevated public podium garden. The group said it has been designed by landscape architect SLA and wraps a 350-metre perimeter around the tower, providing an open-air sanctuary and 360-degree viewing platform for City workers and visitors. At ground level, the scheme delivers 42,700 square feet of new SLA-designed public realm with 350 public outdoor seats.
There is 111,000 square of amenity space for tenants. There is a 400-seat double-height auditorium on Levels 9 and 10. Level 71 will be set aside for tenant entertaining and the highest bar in London, with further tenant amenity across Levels 8, 12 and 13. Private occupier terraces are on Levels 30 and 48. On the lower ground floor there is a lounge, bar, wellness suite and fitness space with facilities for cyclists.
One London is exploring certification against BREEAM and NABERS UK rating frameworks, the developers said. The all-electric building will operate with greywater recycling and rainwater harvesting throughout. The design reuses the existing basement and foundations to minimise embodied carbon, while a layered landscape strategy delivers a 960% Biodiversity Net Gain and a near five-fold increase in Urban Greening Factor across the site.
Aroland Holdings is advised by Perennial Holdings, a Singapore-based real estate developer and investor.
Pua Seck Guan, chairman and CEO of Perennial Holdings, said in a statement: “One London symbolises our commitment to delivering buildings of international significance that will leave a lasting legacy. The name captures what this building truly is: the defining address of a city like no other."
The developers said Knight Frank data shows that London office take-up reached 12.1 million square feet in 2025, while up to 50 million square feet of leases are set to expire by 2030, intensifying competition for the next generation of Grade A workspace.
David Camp, chief executive of Stanhope, added: “One London will be a striking addition to the capital's skyline and serve as a symbol of its enduring global pre-eminence. With London office take-up at its strongest level since 2019, 70 of 98 major deals last year involving expansion, and vacancy for new City Core space at just 0.3%, the case for delivering the next generation of globally competitive workspace has rarely been clearer.
“London is not short of offices in general. It is short of the very best offices that help businesses attract talent, collaborate and grow. Delivering elegant buildings that redefine how we think about the workplace, and that are woven into the fabric of London, its occupiers, businesses and communities, has been the foundation of our 35-year track record of delivering pioneering and ambitious developments.”
Eric Parry, founder of Eric Parry Architects, the architect on the building, said: “One London stands as an icon at the centre of a great city with a confident future in its global role and outreach. London has evolved around the 'Square Mile', essentially the Roman city, over the last two thousand years, adding with each historical twist and turn layers of building and conversation of every period since. We stand at an historic moment of physical metamorphosis as the City rises in a uniquely close and tall form, at the centre of which is One London."
Newmark has been appointed as leasing adviser for One London.