At that time a Joint Executive Council was formed with the existing structures of the NUT and ATL continuing to function as sections of the new union.

The origins of ATL go back to 1884 when 180 women met to create the Association of Assistant Mistresses (AAM).

Between 1899 and 1908 it played an influential part in obtaining security of tenure for assistant teachers through the Endowed Schools Act.

In 1978 AAM and AMA merged to form the Assistant Masters and Mistresses Association (AMMA), with a membership of approximately 75,000.

The NUT and ATL agreed to pursue a merger during their Special conferences held on 5 November 2016.