It has been home to two MPs, the Sassoon family of Baghdadi financiers and a base for the Red Cross.
Now 17 Belgrave Square in Belgravia is to be turned into a single home valued at £110 million, making it one of the most expensive residences in London.
More recently the headquarters of the Royal College of Psychiatrists, the Grade I listed building between the Austrian Embassy and the London branch of the Country Land and Business Association is being redeveloped after standing vacant for several years. The work will be completed next summer.
“It's the square for royalty and world leaders and [properties] come to market only very rarely,” said Sanjay Sharma, co-founder of developers Fenton Whelan, which is behind the project.
He told The National it is an extremely unusual “speculative development” at the very high end of the market, but it “reflects our conviction that London will always remain a very attractive place for the world's elite”.
Mr Sharma said 17 Belgrave Square would be a single family residence of 22,000 square feet in “possibly the best square” in London and would be marketed from early 2026.
Any prospective buyer would most likely be a billionaire who “lives globally”.
Fenton Whelan has a track record of developing multi-million-pound projects in the UK capital. It is also behind Park Modern overlooking Hyde Park, where the penthouse is on sale for £60 million. Mr Shah said it has proved popular with buyers from the Middle East due to rising property prices in the Gulf and a flatlining in London.
Buyers from the Gulf have driven sales of super-prime homes priced above £15 million ($19.6 million) across central London over the past four months, according to luxury property agency Beauchamp Estates.
Almost 30 per cent of the 27 super-prime properties sold have been bought by Middle East purchasers, most notably from the United Arab Emirates, Saudi Arabia and Qatar, it found.
Giga market
But 17 Belgrave Square’s price tag puts it beyond super-prime (£15 million to 100 million), and into the giga-prime market.
Peter Wetherell, executive chairman of Wetherell, an estate agent specialising in London’s prime residential area of Mayfair, said the giga-prime market was “very elite and specialised”.
“There are currently only around 20 mega-residences in London valued at over £100 million,” he told The National. They are located in just a handful of addresses – Mayfair, Belgravia, Knightsbridge, Regent’s Park, St John’s Wood, Kensington and Hampstead.
“These £100 million-plus homes are just two types – either vast mega-mansions or huge penthouses. They are truly unique trophy assets,” Mr Wetherell said.
“The giga-prime homes market is dominated by buyers from just a small number of countries: Qatar, India, UK, America, UAE, Saudi Arabia and China.”
Not many cities in the world contain properties reaching such high prices. Outside prime central London, the only other locations with giga-prime residences are Dubai, Monaco, the French Riviera, Manhattan, Beverly Hills, Singapore and Hong Kong. “So, globally, it is also an extremely rare and elite marketplace,” he said.
“All the buyers are billionaires and many are heads of state or royals from the Middle East. So, by its very nature, it’s an extremely private and policed marketplace.
“The sales are rare, and the opportunity to buy a giga-prime residence only comes up very occasionally. Nearly always the sales are on a strictly off-market basis, with the deals cloaked in secrecy and legal non-disclosure agreements,” Mr Wetherell added.
Discretion is everything when dealing with the buyers of such properties, he said, because they like to be extremely private for security reasons.
Historic address
As its name suggests, Belgrave Square is at the heart of Belgravia, one of the largest garden squares in central London. It is primarily a base for embassies, including the newly reopened Syria embassy at number 8, Kuwait (11A), Brunei (19-20), Germany (21-23), Spain (24), Bahrain (30), the Saudi Cultural Bureau at 29 and Turkish embassy at 43.
The square contains statues of Christopher Columbus, Prince Henry the Navigator and Simon Bolivar. It was the brainchild of the 2nd Earl Grosvenor, later the 1st Marquess of Westminster in the 1820s and takes its name from one of the Duke of Westminster’s subsidiary titles, Viscount Belgrave, after a village in Cheshire.
Some of the richest people in society lived in the square during the 19th century, before the buildings were acquired by institutions in the 20th century. During the Second World War, it was used as a tank park.
Number 17 has only had five tenants since it was completed in the 1840s. The first was Sir Ralph Howard, a wealthy landowner and Whig politician who presented petitions for the abolition of slavery, and would entertain his neighbour, the Duchess of Kent, the mother of Queen Victoria.
Next, in 1870, came Pandeli Ralli, a Greek-British Liberal politician born in Marseille, France, who was also a shipping and textiles tycoon. During the First World War he placed the property at the disposal of his friend Lord Kitchener, Secretary of State for War, who used it as his London headquarters.
In 1929 it was bought by the billionaire Sassoon family from Baghdad, who had extensive banking, property and industrial interests in India and Hong Kong. It served as the London home of Lady Leontine Sassoon, where she lived in grand style until 1955. During her time the home was also used as a supply depot for the Red Cross and she is said to have held parties for soldiers during the war.
It was later converted to commercial use, and from 1956 served as offices first for the Institute of Metals until 1974 when the Royal College of Psychiatrists moved in, staying for the next four decades.
