ABTAPL was originally formed to be the United Kingdom member of an international Association of Theological Libraries which was set up in 1954, following a meeting convened by the World Council of Churches under the auspices of UNESCO.
It was felt that there was a strong need for wider dissemination throughout the world of information about theological libraries, librarianship and literature. Unfortunately, this international organisation did not long survive, but many of its aims and objectives are carried out by the Bibliothèques Européenes de Theologie (BETH), of which ABTAPL is a member.
This article by Judy Powles, originally published in the ABTAPL Bulletin in autumn 2020, gives further detail about the history of the association.