Based in the Potteries, it was the first union to actively recruit members from outside the area, and focused its efforts on building its strength, and opposing the worst truck shops.

[7] This membership fell during the 1920s and much of the 1930s, as the Great Depression hit, and the union struggled to increase the low wages paid in the industry.

In 1975, the union signed a closed shop agreement with the British Pottery Manufacturers' Federation, although workers who did not wish to join could pay the equivalent amount to a charity.

The agreement also established an approach to calculating wage increases, and gave workers two extra days holiday each year.

[11] The union sponsored its general secretary as a Labour Party candidate in several Parliamentary elections.