The creation of the World Federation of Trade Unions in October 1945 was intended as a major step towards international trade-union unity. Less than four years later, in January 1949, the secession of its British, American and Dutch affiliates, soon to be followed by the bulk of Western trade union centres, left the international labour movement more divided than ever. Narrative accounts of the WFTU's brief life as a united body and of the developments leading to the schism have long been available and are not matters of contention. As to the cause of the split, however, there is less agreement. The ostensible reason for the secession was the failure of the WFTU to reach agreement with the International Trade Secretariats (ITSs) on their relationship with one another. Those who split away always contended that disagreements over trade-union matters led to the rupture. In recent years, however, with the opening up of national archives, attention has turned to the influence of governments in the field of international trade unionism. In particular the interventionist role of the US State Department acting through the American Federation of Labour has been chronicled. However, as yet no full account of the activities of the British Foreign Office in this area is available. Given the fact that the British Trades Union Congress was the instigator of the schism and the single most influential union centre to leave the WFTU, an examination of Foreign Office relations with it would seem to be warranted. Equally the relationships between the Foreign Office and the State Department and between the TUC and the American Congress of Industrial Organisations, the two principal Western centres in the WFTU, are matters of considerable interest.