 In 1957 A. R. Topman became an assistant general manager, and about 40 years later his son, Simon Topman, became the owner and the managing director of the company, starting the fourth period of company developments.In 1998, Simon Topman and Martyn Gilchrist co-authored a book titled "Collecting Police Whistles And Similar Types".The factory name was changed to Acme Whistles and makes about 5 million whistles each year.