Open House Festival

25 Cannon Street

walk/tour, public realm/landscape, offices

Buckley Gray Yeoman, 2022

25 Cannon Street, EC4M 5TA

Situated adjacent to St. Paul’s Cathedral, our reworking of this six-storey neo-classical building has created 116,000 sq ft of high-quality office space, three levels of communal terraces and a large new garden designed by Tom Stuart-Smith

Getting there


St. Paul's, Mansion House


8, 521, 26, 25, 17, 15, 11

Additional travel info

TUBE Mansion House Underground Station Circle, District lines BUS Mansion House Station - 1 min. walking / 38 metres 11, 15, 17, 25, 26, 521, 8, N11, N15, N199, N21, N242, N25, N26, N550, N551, N8





Originally designed by Jean Paul Carlhian in association with RHWL Architects in 2001, the existing building lacked daylight within the office floorspace and had no external amenity space for the public or the building’s users. We were asked to significantly remodel the building to deliver an attractive, modern workplace, complete with improved floor to ceiling heights.

In addition to being close to Grade I listed St Paul’s Cathedral, the building sits opposite 30 Cannon Street (given Grade II listing in 2015) and Bracken House (Grade II* listed in 1987). It also sits beside Jean Nouvel’s One New Change shopping centre.

Green Space

A bold and contemporary new public garden which contributes to the sequence of green spaces adjacent to St Paul’s Cathedral.

Additionally, we have worked alongside landscape architect Tom Stuart-Smith to create a new garden immediately in front of the building where existing trees have been retained alongside new shrubs and understorey planting that will provide round-year interest and ground coverage to the redeveloped space. The garden had previously been a plain lawn with limited interest, but a considered redesign and new planting strategy will now provide seclusion and protection from the busy surrounding area, creating a more dynamic and varied space for the building’s users and passers-by ,to explore and move through.

In the garden’s centre is a large, reflective pool designed in collaboration with water feature specialist Andrew Ewing. This reflects the sky and surrounding historic environment on its surface and serves as a light-well for basement space below.

Natural habitats in the heart of the City

In recognition of the City of London Corporation’s Climate Action Strategy, developer and asset manager Pembroke redeveloped 25 Cannon Street with sustainability at its core, resulting in excellent results for embodied carbon and operating on renewable power.
Situated next to St. Paul’s Cathedral, architects Buckley Gray Yeoman were appointed to reimagine a six-storey neo-classical building into a building for the future, boasting a spectacular series of terraces and a large new garden by award winning landscape architect Tom Stuart-Smith, which recognises the vital role that natural habitats play in absorbing carbon dioxide from the air as well as increasing biodiversity.
The roof terrace offers an incredible 360-degree view of London and features planting chosen to provide colour, variety, and interest throughout the year.
A new garden situated at the entrance of 25 Cannon Street retained existing trees and added new shrubs and ground coverage. A large, reflective pool designed in collaboration with water feature specialist Andrew Ewing reflects the sky and surrounding historical environment, providing calm in the bustling heart of the City.


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