This palatial blue-plaque townhouse on South Street is for sale for the first time in twenty years. The seven-storey 6,477 sq ft townhouse overlooking Mount Street Gardens was once the home of Lord Ashfield, the celebrated First Chairman of London Transport and founder of the London Underground. The plaque bearing his name is almost unique, recognising his life's work by using the iconic London Underground typeface that he helped to design.

This classically elegant Grade II Listed freehold house was built by J.J Stevenson, master of the Queen Anne revival style, between 1896 and 1898, and retains many of its original features. Located on “one of Mayfair's most architecturally beautiful streets,” it provides an impressive family home with its six sumptuous bedrooms and a lavish space for entertaining, with ceiling heights of 3.5m in the formal reception rooms. Its two rear balconies offer magnificent views over Mount Street Gardens, which pre-date the house by nine years and house a variety of exotic plants including a Canary Island date palm and three dawn redwoods from China.

The house is laid out over seven levels, comprising lower ground, ground and five upper floors connected by an impressive cantilevered staircase, and offers a breathtaking example of Queen Anne Revival Style architecture. Guided by the Victorian obsession with looking back and seeking to improve styles of the British past, the architect Stevenson emulated the grand buildings of Queen Anne's reign, designing with a focus on classical beauty - balance, harmony and light. As a result, the house is characterised by high ceilings, impressive windows and elegant cornicing, to achieve an effect of symmetry and order.

The lower ground floor contains an impressive family kitchen/dining room with a large central island, aga-style ovens and a great ornate fireplace. To the front there are staff quarters and an assortment of storage rooms and facilities. The ground floor has an entrance hall with diamond-patterned marble flooring, and leading off it are the elegant study with bay windows, and grand formal dining room capable of seating eighteen guests. Like many rooms in the house, it benefits from a stately original marble fireplace, ceiling cornicing and impressive windows.

The first floor contains a huge drawing room and enormous 11m x 4m reception room with high ceiling and floor-to-ceiling windows, while the second is dominated by the extravagant principal bedroom suite. This luxury living space is large enough to be used as another room for entertainment in the day and gives access to the main bathroom and vast walk-in dressing room with its own bay windows. There are five further bedrooms on the third, fourth and fifth floors, while the impressive fifth-floor roof terrace offers stunning panoramic views over Mayfair.

South Street is enviably located in the heart of Mayfair, just moments from the charming Mount Street Gardens. There is a wonderful range of amenities and local culture nearby, with the luxurious, world-renowned shopping streets of Bond Street, New Bond Street and Savile Row all located within close proximity.

Berkeley Square is a short walk from the property and plays host to exclusive private members clubs such as Annabel's and famous restaurants such as Sexy Fish. Hyde Park and Green Park offer tranquil green spaces nearby if one wishes to escape the hustle and bustle of the Mayfair District. The nearest underground station is Green Park (Piccadilly, Victoria and Jubilee Lines).