The initial creation of UKAT was overseen by an advisory panel of archivists together with a group including representatives of family history societies and archive users organisations. Since 2004, AIM25 (Archives in London and the M25) has steadily added to the subject thesaurus with the addition of new terms and vocabularies, chosen and validated by archive professionals. Ongoing curation and maintenance of the thesaurus is now carried out on a voluntary basis by the AIM25 team and by IMAGIZ.