A sub-penthouse property in London with links to banking, diamonds and royalty is up for sale, priced at £39.5m ($52m).

The four-bedroom flat in the Clarges Mayfair building at 82 Piccadilly has two rooftop terraces overlooking Green Park.

The building, built as an office in the 1960s before being redeveloped in 2019 as luxury apartments, has long been a spot for extraordinary wealth.

The plot was originally the site of the Pulteney Hotel, built in 1740 for the Earl of Bath, part of the aristocratic Pulteney family, and considered one of the best in London. It was one of the first in the city to have a flushing indoor toilet which won the approval of the Russian Grand Duchess Catherine when she stayed there.

The interior of the four bedroom Mayfair sub-penthouse overlooking London’s Green Park. Photo: Grant Silverman / Wetherell

It was replaced in 1821 as a vast four-storey mansion called Bath House, the home of financier Alexander Baring, 1st Baron Ashburton, from the family behind Barings Bank. The bank was founded in 1762, surviving more than two centuries before it was brought down by rogue trader Nick Leeson in 1995.

Bath House was later home to the aptly named railway baron, Baron de Hirsch, who built the Orient Express line through the Ottoman Empire connecting Vienna to Istanbul.

Portrait of Alexander Baring, Lord Ashburton, owner of Bath House at 82 Piccadilly. Photo: Grant Silverman / Wetherell

It was bought in the early 20th century by South African diamond magnate Sir Julius Wernher and his socialite racehorse-owner wife Lady Ludlow, when the house was written about as “the Millionaire’s Home”.

Wernher controlled the De Beers mining and diamond company and at the time was the richest man in Mayfair. He added several floors and attic space to Bath House which at the turn-of-the-20th century was the largest mansion on Piccadilly.

When Wernher died in 1912 Bath House was inherited by his son Sir Harold Wernher who, in 1917, married Countess Anastasia Mikhailovna, the daughter of Grand Duke Michael Mikhailovich Romanov of the Russian imper