[1] The site had a 71-foot (21.64 m) frontage on both Piccadilly and on Jermyn Street (rear entrance) with a footprint of about 11,000 sq ft (1,022 m2) [1] and an easy walking distance from Savile Row.

It cost such a price that Alexander Simpson warned that the company was not expecting to earn a profit for several years after due to his determination to create something of such high quality[5] (for which it later won awards).

[citation needed] László Moholy-Nagy, a director of the Bauhaus school,[6] designed much of the visual merchandising and displays for the shop, including the in-store signage, the window displays, and three aircraft to be exhibited on the fifth floor at the store opening merely to draw in curious customers, attract headlines and increase footfall [7] (the door framing had to be removed to allow the aeroplanes into the building and suspected to have been winched up the centre of the staircase).

[7] The building is recognised as Joseph Emberton's masterpiece – the front glass and stone strips are not quite horizontal as perceived on first glance, but at a slight angle to help appear more horizontal, keep clean for longer and reflect the coloured neon lighting that was in place at the opening; ducts are hidden around the walls so that the lights in them reflect better off the ceiling, the water supply was by an artesian well in the basement; the vast open floors which were uncommon at the time, fitted with hidden sliding fire doors; a vacuum cleaning system with vertical tubes installed through the building and in the ceiling ducts; the use of new coloured neon-lighting for the front of the shop that he'd used at the Blackpool Pleasure Beach before; and having the first curved-glass windows in Britain.

[10] The shop's performance was successful, renowned for the window displays and was considered a sight for London, and as planned by Simpson, the fourth floor was designated for womenswear a year after opening.

[citation needed] During the Second World War, Simpson Piccadilly was one of the largest stores to stock wartime uniform for soldiers, providing for both men and women officers and civilians.

[11] In the early 1950s, scriptwriter Jeremy Lloyd was employed as a junior assistant at Simpson; he drew on his experiences to come up with the idea for the highly popular 1970s/80s television sitcom Are You Being Served?