Mayfair’s most unusual, ultimate “Party Pad” for socialites who love entertaining, has just come onto the market at 17 Grosvenor Square in Mayfair with Wetherell.

Priced at £5.5 million the 1,658 sqft 2/3 bedroom 2nd floor apartment has two spacious reception rooms and kitchen/breakfast room, with south facing windows overlooking Grosvenor Square.

What makes the property highly unusual, and a real catch for a Mayfair socialite, is that the apartment has totally-free-of-charge access and use of a gigantic ballroom on the ground floor of the grand apartment building and also a series of maid’s rooms and parking, which can be rented (subject to availability).

The grand brick and stone apartment building was built at 17 Grosvenor Square in 1958 and was designed to provide homes perfect for grand entertaining. The building has an elegant entrance foyer, grand communal corridors and a ground floor ballroom which can be used by residents of the building. An illustration produced in 1958 shows how elegant the ballroom looks when used for grand social functions.

The ballroom is 55 ft by 22ft in size, with a 20ft high ceiling, with access to a kitchenette at one end. The ballroom can accommodate a cocktail party for 350 people or a sit down dinner for up to 200 guests.

The ballroom provides the perfect venue for a cocktail party, wedding celebration, Bar Mitzvah, ball or white-tie dinner party.

Wetherell highlight that the average ballroom hire costs for a Mayfair ballroom range from £7,000 to £10,000+ for a day/evening, so if the ballroom was used by the apartment owner 12 times a year this would be a cost saving of up to £120,000 a year, and if used 24 times a year, a cost saving of up to £240,000 a year, and if the ballroom was used 365 days a year, a cost saving of up to £3.65 million. If the ballroom was used daily for the entire duration of the apartment’s 43 year lease the open market hire cost of this would be up to a staggering £156.95 million. Naturally the ballroom is only used by residents a few times a year for VIP events.

Grosvenor Square has always been favoured by the rich and famous, notable past residents include the infamous Duchess of Argyll, the Onassis family, Lady Cunard, Johnny (Earl) Spencer (father of Diana Princess of Wales) and Sir Ernest Cassel (grandfather of Countess Edwina Mountbatten).

Peter Wetherell, Managing Director of Wetherell said: “This spacious apartment is perfect for a socialite wanting space for entertaining and staff. Its not often that you can buy a Mayfair home with access to a 350 person ballroom and maid’s rooms.”

The apartment is currently for sale for £5.5 million, on a 43 year lease, with a ground rent of £135 per annum and a service charge of £21,980 per annum. If the lease was extended to 120 years this would cost up to £1.3 million and would re-value the apartment at circa £7.5+ million.