Beauchamp Estates and Clifton Property Partners have successfully sold, to an ultra-wealthy incognito buyer, a magnificent £22 million 6,949 sq.ft. seven bedroom Freehold mansion on Park Street in Mayfair, formerly the Icelandic Embassy and originally the home of the Chairman of Arsenal Football Club: the trophy deal is the biggest house sale in Mayfair during the first six months of 2025.

Yahya Swallem, Senior Sales Negotiator at Beauchamp Estates introduced the buyer, working in conjunction with Robert Windsor, Co-Founding Director of Clifton Property Partners, who was instructed by the vendor. The agents worked closely together in advising the purchaser and vendor.

The mystery buyer wanted a turn-key, ultra-prime family home, which provided security as well as a good long-term investment in Mayfair, London’s most sought after address.

With a brick façade, tall sash windows and stucco detailing in the classical style of Sir Christopher Wren, the five storey mansion on Park Street provides substantial accommodation over lower ground, ground and four upper floors. Features include a grand staircase, passenger lift, private roof terrace garden and direct access, exclusive to resident’s only, of the Green Street Gardens.

Fully refurbished and modernised for 21st century Mayfair living, the lavish interiors were designed by award winning Dutch designer Marcel Wanders of Marcel Wanders Studio.

The house provides a spacious entrance hall and four reception rooms over the ground and first floors. The VIP principal bedroom suite, with bedroom, walk-in dressing room and main bathroom has its own private level on the second floor, with four further bedroom suites (three ensuite) on the upper floors. There is a kitchen/breakfast room and two bedrooms on the lower ground floor.

The Edwardian mansion on Park Street has a colourful history that combines sports and diplomatic use. The property was originally designed by Wimperis and Simpson in 1913 and built in 1924-1925 by George Trollope & Sons, the local Mayfair builders who constructed Claridges Hotel.

After being fitted out in the late 1920s the first resident from 1934 onwards was Robin Vane-Tempest-Strewart, Viscount Castlereagh, an aristocrat, MP and football fanatic who served as Chairman of Arsenal Football Club.

As the London home of the Chairman of Arsenal Football Club the Park Street mansion hosted noted Arsenal footballers during the 1930s including Cliff Bastin, Eddie Hapgood and Pat Beasley.

In 1949 Robin Vane-Tempest-Strewart succeeded his father as the 8th Marquess of Londonderry and the Park Street mansion, which had been unoccupied since 1941, was sold to the Government of Iceland, becoming the Icelandic Embassy and Ambassador’s residence, a role it retained for almost 60 years, up until 2008.

As the Icelandic Embassy the Park Street mansion was at the centre of a diplomatic storm between the UK and Iceland during the 1950s and 1970s, the so-called “Cod Wars”, when Royal Navy and Icelandic Coast Guard ships rammed each other in disputes over fishing rights in Icelandic waters. The dispute was resolved by Prime Minister James Callaghan in 1976 with UK trawlers given access to Icelandic waters.

From 2000 onwards, three Icelandic banks – Kaupthing, Landsbanki and Glitnir – multiplied in size and became major lenders in the UK property industry. During this period the Park Street Embassy hosted the “great and good” of the London real estate sector.

As the 2008 global financial crisis unfolded all three Icelandic banks collapsed and the Icelandic economy plunged into recession. So severe was the financial downturn that the Government of Iceland was forced to sell the Embassy building on Park Street and relocate to shared offices on Hans Street in Knightsbridge.

Following the sale the Park Street building was converted from diplomatic premises back into a private single house, and was sold again in 2011 with a full refurbishment and modernisation undertaken to create the modern trophy home that has just been sold by Beauchamp Estates and Clifton Property Partners.

Yahya Swallem, Senior Sales Manager at Beauchamp Estates says: “Beauchamp Estates are delighted to have introduced the buyer who wanted a turn-key luxury family home in the heart of Central London in Mayfair, arguably the capital’s premier and most sought after address. We worked seamlessly with Clifton Property Partners resulting in this landmark deal, which is the most expensive house sale in Mayfair so far in 2025.”

Robert Windsor, Co-Founding Director of Clifton Property Partners says: “We are delighted to have successfully negotiated the sale of this magnificent Freehold mansion on Park Street which shows the resilience of the Prime Central London market. Impeccably interior designed and dressed by Marcel Wanders Studio, the house was sold “turn-key” which is what most of our buyers seem to be looking for at present. Buyers in Prime Central London want dressed, turn-key homes which can be moved into immediately without the need for modernisation work. This trophy home deal is a text book example of this. It was a real pleasure dealing with Yahya Swallem on this transaction and we worked closely together to ensure a swift and seamless sale.”