In a consultation last month, the C20 society said it ‘strongly recommended’ listing 10 Cabot Square, a 10-storey office by SOM in the Chicago Neoclasssical style, which is currently subject to partial demolition under plans drawn up by Howells.

Under the plans for Canary Wharf Group, submitted to Tower Hamlets in January, only the foundations and primary structure of SOM’s 1991 office building in Canary Wharf’s North Dock would be retained.

Howells’ scheme would add three storeys to the 35-year-old building plus a roof plant level, introduce internal reconfiguration, and swap the current PoMo-Neoclassical frontage for a bright-red ‘high-performance’ façade.

The C20 Society told the AJ it considers 10 Cabot Square ‘the finest example of this type of architecture remaining in Canary Wharf’ and ‘an exceptionally well-designed synthesis of the early Chicago skyscraper and its London context’.

‘Olympia and York’s requirement for Canary Wharf was that it was “quintessentially Postmodern in its desire for a development that looked rooted in place and time”,’ said the campaign group about SOM’s original 1985 masterplan for Canary Wharf.

The society added that 10 Cabot Square was ‘resolutely American in its stylings, with Sullivan-like ornament and a high-quality façade system of brick and stone-clad panels, meeting more traditionally British features such as the arcades’.

Howells said in planning documents that, while the 1991 building’s steel frame and foundations could be reused, the current Neoclassical façade had deteriorated over time and ‘contributed to adverse effects on the building’s performance and aesthetics’.

The atrium and office floors will be reconfigured to allow for the introduction of terraces and daylight into the building, Howells added. On the ground floor, active uses will be introduced that ‘may include retail, entertainment and food and beverage units’.

The AJ understands Historic England carried out a consultation in early March but has not yet carried out a formal assessment on 10 Cabot Square. Any recommendation would then go to the Department for Culture, Media and Sport to make a final decision.

Both C20 and Historic England are consultees on the Howells scheme. The C20 Society has objected to the planning application while HE has said it ‘has no objection to the application on heritage grounds, subject to the outcome of the listing application’ and that the building has ‘some architectural quality’.

Canary Wharf Group and Howells declined to comment.