Plans drawn up by the south London firm for the Grade II-listed embassy on Montagu Place were given consent by Westminster City Council last month (16 April) for major internal and external works to the building on Bryanston Square.

Westminster planning officers had earlier recommended approval of the Dow Jones scheme, which features retention of the north, south and west façades, plus a single-storey extension to the current visa hall and rebuilding of the fifth storey.

Dow Jones said in planning documents that internal reconfigurations would ‘better suit the working practices of the embassy’, which has occupied the site for more than 100 years, while improving energy efficiency.

Spaces due to be refurbished include the chancellery along with an area for Switzerland Tourism, several multifunctional semi-public interior spaces, offices for state representatives and serviced flats.

Once complete, overall floorspace will increase marginally from 6,845m ² to 6,857m ² across all the embassy’s buildings.

The scheme is aiming to achieve BREEAM Excellent and will be operationally net zero thanks to thermal efficiency improvements and the installation of air source heat pumps, solar panels and an ‘energy generating’ east façade, Dow Jones says.

The current embassy was built in 1971 to designs by Swiss architect Jacques Schader, and includes a Grade II-listed Georgian-style mansion façade with a Modernist annexe.

The Swiss Government says the building was beginning to ‘display significant functional, energy efficiency and organisational shortcomings’.

Switzerland has undertaken a range of embassy upgrades around the world in recent years, including an extension to its Berlin chancellery by Diener & Diener Architekten, a new visa office in Beijing by EXH Design, and the conversion of a 1960s house into an embassy for Ivory Coast by Localarchitecture .

South London-based Dow Jones was selected last summer ahead of Witherford Watson Mann, Dave Kohn Architects and Jonathan Tuckey to win the Swiss government’s commission to work with Zurich-based Studio DIA to refurbish the embassy building.

A feasibility study for the upgrade was carried out by London-based Atelier 5 and Gensler.

Meanwhile, Corstorphine & Wright's Vietnamese Embassy and Consulate scheme to alter and refurbish the existing Vietnamese Embassy and Consulate in Kensington, central London, was approved in February by Kensington and Chelsea.

The practice was appointed to the job last summer alongside consultant LXA Projects .