Modern services and biodiversity enhancements breathe new life into a historic office building in central London

Threefold Architects has completed a 23,000 sq.ft retrofit of 12 Little Portland Street, a grade II-listed building close to Oxford Circus, for The Crown Estate.

The project seeks to revitalise the 1920s neo-classical office building, incorporating flexible office spaces and upgraded energy performance measures while preserving its heritage features.

The design is intended to address post-Covid workspace trends, focusing on smaller, more flexible spaces suited to hybrid working. According to Threefold, the scheme aims to diversify The Crown Estate’s commercial portfolio by attracting a mix of tenants through inclusive layouts and amenities that promote collaboration and well-being. 

Significant upgrades have been made to the building’s thermal performance, with new mechanical and electrical systems installed, including a high-efficiency recovery condenser and modernised ventilation systems.

Heritage features such as period windows and plasterwork have been refurbished or echoed in new design elements. A full façade restoration was undertaken, alongside the replacement and refurbishment of glazing, which contributed to achieving a BREEAM Very Good rating.

Existing materials, including raised access floors, were catalogued and reused where possible, aligning with circular economy principles.

Internally, the six floors of workspace are designed to accommodate contemporary work practices. Threefold describes the spaces as a mix of task-specific work areas, breakout zones, and collaborative areas, with natural materials and planting used to create a comfortable environment.

A key addition is a new roof terrace, which transforms previously unused space into an outdoor area for events and relaxation, offering views of central London. The terrace includes planting to support The Crown Estate’s “Wild West End” strategy, aimed at improving air quality and urban biodiversity. Features such as bee blocks and insect habitats have also been integrated.

Project data

Client: The Crown Estate

Architect: Threefold Architects

Project Manager: Dendy Byrne

Structural Engineer: HTS

M&E: WPP

Environmental: WPP

Heritage Consultant: Donald Insall Associates

Planning Consultant: Gerald Eve

Completed: October 2024

Gross internal area: 23,000 sq/ft

Photographs: Jack Hobhouse

Suppliers

Lino: Gerfloor

Terrazzo: Inopera Kitchen worktop, Diespeker for Stairs

Furniture: Rawside, Ondaretta, Vitra, Pearson Lloyd

Sanitaryware: Crosswater

Recycled Paint: Paint 360

Tiles: Grestec

Bespoke Joinery: Falkus Joinery

Terrace Planters: Raaft

Wall lights: Holloways of Ludlow/ Artimede

Decking: Raaft

Terrace Handrails: BA Systems

Blinds: Waverley

Insect hotels: Green and blue

Bird bricks: manthorpe