At just under 310m, One London provides lots of public space and fills a gap in the Grade A market, developer says.
Aroland Holdings, a consortium of Southeast Asian investors, said today it would appoint a main contractor this year for the $1bn-plus One London office tower, which is set to be the tallest in the City of London.
Reaching 309.6m, it will also share the title of the UK’s tallest building with the Shard in Southwark.
The scheme was known as 1 Undershaft when it received full planning consent from the City of London Corporation in December 2025.
Aroland said it would be “one of the capital’s defining buildings of the next decade”, with 1.2 million sq ft of office space, green spaces and 42,700 sq ft of public realm at ground level, including 350 public outdoor seats.
In all, 125,000 sq ft will be freely accessible to the public, making the tower one of the capital’s most publicly accessible tall buildings.
At Level 11, an elevated public podium garden designed with landscape architect SLA will wrap a 350m perimeter around the tower, providing a 360-degree viewing platform for visitors.
London Museum will operate a viewing gallery on Level 73 and an educational feature called “classrooms in the sky” on Level 72.
Construction planned for 2028
If it goes ahead, it will go up at the junction of Leadenhall Street and St Mary Axe, the site of St Helen’s Tower, which Keltbray is now deconstructing.
Construction is planned to start in 2028 after enabling works are complete and development financing has been secured.
Stanhope is the development manager, the architect is Eric Parry Architects, and WSP is providing civil and structural engineering, MEP and sustainability advice.
Floorplates range from around 12,000 to 26,000 sq ft. Every floor has a 3m floor-to-ceiling height to channel daylight.
Aroland said the building would provide some 10% of the net additional office space identified as needed under the City of London’s City Plan 2040.
Highest bar in London
A 400-seat double-height auditorium on Levels 9 and 10 will host presentations and events framed by city views.
Level 71, meanwhile, is devoted to tenant entertaining and the highest bar in London.
Aroland said it’s exploring BREEAM and NABERS UK certifications. The building will be all-electric, with greywater recycling and rainwater harvesting throughout.
It will also reuse the existing basement and foundations to minimise embodied carbon, while the landscape strategy delivers a 960% biodiversity net gain and a near fivefold increase in Urban Greening Factor.
Is this needed?
Despite the economic gloom, the development team believes One London will address what it calls an acute undersupply in London’s prime office market.
There, it says, demand is concentrated in the highest-quality, most sustainable and best-connected buildings.
Up to 50 million sq ft of leases are set to expire by 2030, intensifying competition for the next generation of Grade A workspace, the developer said.
Stanhope chief executive David Camp said London office take-up was at its strongest level since 2019 and that vacancy for new City core space stood at just 0.3%.
“London is not short of offices in general. It is short of the very best offices that help businesses attract talent, collaborate and grow,” he said.
