One Great St Helen’s City of London office building, British capital skyscraper design, Eastern Cluster images
12 January 2026
JRA repositions One Great St Helen’s nearly three decades after completing original building
Design: John Robertson Architects (JRA)
Location: Eastern Cluster, City of London, England, UK
Photos © Jack Hobhouse
One Great St Helen’s City of London Office Building
John Robertson Architects (JRA) has completed the refurbishment and extension of One Great St Helen’s, an office building in the heart of the City of London’s Eastern Cluster, adjacent to the St Helen’s Conservation Area.
JRA was appointed in 2021 by Rafer Investments Ltd – on a project led by CBRE Development Management – to re-imagine and update the current building to meet contemporary leasing standards – whilst also aligning the building’s operation with the owner’s ESG aspirations. The original building, designed by Hurley, Robertson & Associates – the predecessor to JRA’s current practice – was completed for client Greycoat in 1998.
Situated just off Bishopsgate, next to the Commercial Union Tower, the area around One Great St Helen’s is characterised by a varied urban context. Since One Great St Helen’s was completed, the surrounding district, now known as ‘The Eastern Cluster’, has changed dramatically in the last 20 years with new office towers being built, including The Leadenhall Building, 22 Bishopsgate, and 8 Bishopsgate and the forthcoming 1 Undershaft.
Hurley, Robertson & Associates’ original design – based upon the firm’s ethos of contextual civic modernism – provided what was considered at the time to be market-leading workspace across nine levels. This centred upon an elegant, curved façade, responding to the winding contour of the Undershaft.
One Great St Helen’s was one of the first office buildings in the UK to be designed to the newly published British Council for Offices Specification and was awarded the BCO Award for Best Commercial Office Building (Southeast) in 2000.
The curved glass frontage facing Undershaft extends between two red sandstone ‘bookends’ which take their design language from the smaller scale urban spaces of Crosby Square – and the adjacent Grade 1, 13th century Great St Helen’s church, which the City Corporation recognises as “one of the most important pieces of medieval fabric surviving in the City.” These bookends comprise wide bay windows that were designed to maximise natural light into the office space.
JRA’s original design context surrounding the site, and the renovated building continues to respond sympathetically to the cluster of new towers, while the new design introduces some innovative design elements to the interiors. This upgrade has focused on renovating office floor levels 1 to 9, whilst also remodelling the entrance hall, the creation of amenity space on the ground floor and the conversion of the basement car park into ‘end-of-trip’ space containing cycle parking, showers and changing facilities.
A new winter garden and landscaped roof terrace has been created on Level 10. This provides a mix of indoor and outdoor amenity space for occupiers and reflects growing demand for open roof terraces among office tenants. The new roof terrace has unique views of the surrounding office towers.
The creation of the enclosed wintergarden – heated in winter and naturally ventilated in summer, offers occupiers a highly attractive amenity floor. The façade incorporates glass louvres and doors which allow occupiers to access the roof terrace.
Recognising the growing trend to incorporate leisure and hospitality elements into commercial office buildings, JRA has fully refurbished the entrance hall and the ground floor offices to modern workspace standards. Meanwhile, new lift designs (produced with specialist consultancy Kone), have been installed, with deep blue interiors complementing the wood panelling and tiling used elsewhere in the building.
A new lightwell has been introduced along the perimeter of the curved façade at lower ground floor level. Previously an underutilised backroom and maintenance area, it had no access to direct sunlight or passive ventilation and fell short of current market standards. The lightwell – a key element of JRA’s design – has transformed the area into a bright, contemporary workplace with framed glimpses of the surrounding buildings.
JRA’s considered application of sustainable design practices has updated the building to meet modern leasing requirements including employee health and wellbeing, low carbon construction methods, and circular economy principles. For example, the retention of original design features – encapsulating JRA’s initial pioneering design and including the modulation of the curtain wall and the fins between cladding panels – helps to mitigate solar gain.
Concurrently, JRA’s approach to minimising demolition and waste, whilst maximising the reuse and recycling of waste materials generated during the refurbishment has resulted in a significantly lower embodied carbon output.
In line with the client’s ESG aspirations, One Great St Helen’s has been designed to achieve BREEAM Excellent Certification.
The inherent embodied carbon savings produced by JRA’s retrofit first strategy has been supported by a building management approach that delivers a predicted 57% reduction in regulated carbon emissions over the Part L2B 2013 baseline.
Combined with the building’s excellent transport connections – with good pedestrian access to Liverpool Street Station and nearby Aldgate – JRA has also transformed the under-utilised car park facilities at basement level into a state-of-the-art, ‘end of journey’ cycle parking, and shower and changing facility for environmentally friendly commuting. This includes ten showers with changing rooms, lockers and toilet facilities and a disabled access shower with an adjoining locker room.
This interior design aims to emulate the look and feel of a premium health centre or spa together with 100 long-stay cycle spaces which represents an increase of more than 40 per cent over the 70 spaces offered by the previous scheme and comprises wall-mounted cycle racks (68), folding cycle lockers (27) and disabled cycle spaces (5).
John Robertson, Founder of JRA & leader of original design team said: “It is tremendously exciting to see One Great St Helen’s being given a new lease of life after almost 30 years. Its reinvention provides a building which is a small jewel in the heart of the Eastern Cluster. It has been cleverly repurposed with excellent new amenities and provides a unique identity for a wide range of city occupiers.”
Zoe Avery, Director, CBRE Development Management said: “CBRE has been a trusted advisor on One Great St Helen’s since our client’s purchase in 2020, providing expertise from planning through to delivery. A strategic repositioning of the building has allowed for increased lettable floorspace, improved energy efficiency and the introduction of flexible amenities, all within a constrained, urban site. One Great St Helen’s is a fantastic example of a high-quality, future-proofed commercial asset that is directly aligned with the wants – and needs – of a modern occupier.”
One Great St Helen’s City of London Offices – Building Information
Development Team:
Design and Monitoring Architect: John Robertson Architects
Commissioning Client: Rafer Investments Ltd
Development Manager: CBRE
Project Manager: B&CO
Planning Consultant: CBRE Planning
Principal Designer: John Robertson Architects
Cost Consultant: exigere
Structural Engineer: Waterman Structures
Services Consultant: chapmanbdsp
Sustainability Consultant: chapmanbdsp
Ecology Consultant: Greengage
Transport Consultant: Arup
Façade Access Consultant: D2E
Security Consultant: Videf
Approved Inspector: Salus
M&E Consultant / Sustainability Consultant: chapmanbdsp
Fire Engineering Consultant: BB7
Acoustic Consultant: Hann Tucker Associates
Main Contractor: OD Group
Delivery Architect: Moxon Architects
Structural Engineer (Delivery): SD Engineers
Principal Suppliers:
External cladding: Schueco UK
External sliding doors: IQ Glass
Ceilings: SAS International
Lighting: Halla UK
Ceramic tiling: Domus, Grestec Tiles
Vinyl flooring: Altro
Furniture buyer: Day2
Terrazzo flooring: In Opera Group
Timber flooring: Havwoods
Terrace porcelain flooring: Raaft
Roof waterproofing: Radmat Building Products
Sub-Contractors:
External cladding: Anglian Architectural
Steel structure: Ermine Engineering
Concrete structure: BTR Building Services
Building maintenance unit: Eurosafe Solutions
Drylining and joinery: ROX Interiors
Glazed screens and balustrades: Northgate UK
Signage: Olympiad Signs
Flooring: Loughton Contracts
Tiling: MTY
Lifts: Kone
Mechanical services: Mala
Electrical services: Paul Earl
Fire alarm system: Ace Fire & Security
Access control system: Ace Fire & Security
Sprinkler system: Select Fire
Environmental Data:
Gross internal floor area: 7,142m²
Gross (internal + external) floor area: 7,571.5m²
Form of contract or procurement route: Design & Build
On-site energy generation: None
Annual mains water consumption: 5.7 m3/occupant (estimated)
New solid external walls: U-value of 0.35 W/m²K
New curtain walls: U-value of 1.4 W/m²K
New and existing slabs: U-value of 0.18 W/m²K
Design Life: 60 Years
Embodied/whole-life carbon: 279 KgCO2eq/m2 embodied; 258 KgCO2eq/m2 whole life
External photo showing original structure at 1 St Helens in 1998:
photo courtesy of architects office
John Robertson Architects (JRA)
Since its formation in 1993, JRA has designed and delivered buildings that have established the firm’s reputation as innovative architects who consistently realise client’s ambitions and resolve complex problems with purpose and flair.
Guided by founder John Robertson, the practice is led by Festus Moffat, David Magyar, Nathalie Bergvall, Etain Fitzpatrick, Angela St Clair-Ford, Mark Wibberley, Anja Schellenbauer and Smita Bhat, supported by an accomplished team of associate directors. JRA operates offices in London, Edinburgh, and Lodz in Poland, and works for clients across the UK and Europe.
JRA’s recent completed projects include the re-imagination of the Northcliffe for DWS, the development of 100 Embankment for X+Y and Salford City Council, the fit-out of the Grainhouse for Helix, the office conversion of the historic industrial space at 9 Devonshire Square for Nuveen, and the creation of the environmentally outstanding workspace Bloom Clerkenwell for HB Reavis.
JRA teams are currently completing schemes within the City’s Eastern Cluster, the Southbank of the River Thames, and across Fleet Street.
JRA are advisors to the UK Net Zero Carbon Buildings Standard in the Office Embodied Carbon Sector, active members of the UKGBC, Sustainable Design Collective and Don’t Waste Buildings. JRA architects have recently written for Real Asset Impact, CoStar, Building Magazine, and Property Week, and presented for the NLA, Surface Design Show, Sustainable Design Forum and Building Design.
Photographs © Jack Hobhouse
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Location: One Great St Helen’s, London EC3, England, UK
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