What is the Portland Works (Aynsley Mill) building?

The Portland Works is a large factory complex built by Aynsley in 1861 on Sutherland Road, Longton. Architectural descriptions note the long, symmetrical façade, central arched entrance and classical style, which stands out from other pottery buildings in the area. The site is widely cited as an important part of Longton's pottery heritage and is directly linked to the development of John Aynsley's business. In modern local parlance, many people refer to the building as "Aynsley Mill". For collectors, the name Portland Works helps to establish stamps that mention Longton or Staffordshire, and this explains why so many Aynsley wares have "England" marks, associated with the Stoke-on-Trent export trade.