Longton China Supplies Ltd did not manufacture ware themselves, they had others produced ware which was marked with the trade name 'Royal Castle Bone China'. 

Originally known as Longton China Supplies Co - a June 1962 newspaper advert reads "Youth, strong, required for carrying ware, good chance for willing worker, age approx. 16 years. Must be experienced in handling china. Apply: Longton China Supplies Co. St. Louis Works."  

The original partners were Mr. McPherson and Mr. Harrison. Later the owners were listed as Ian and Lillian McPherson.

They probably became a Ltd company in 1964. 

Resolutions for winding up and appointment of liquidators were made in September 1998.