[1] He worked for a while in Dublin, during which time he frequently attended the Irish Trades Union Congress and served on its Northern Ireland Committee.
[2] In 1942, he became secretary of the union's Sheffield branch, and was soon elected to its national executive.
After becoming a full-time organiser for the NUVB's York and North-Eastern division in 1951, he was elected as assistant general secretary of the union, in 1953.
His tenure was a difficult period for the union; he was known as a moderate figure and was able to maintain a membership of 85,000.
[1] Roberts negotiated a merger between the NUVB and the Transport and General Workers' Union (TGWU); as part of the agreement, he was due to become an executive officer of the TGWU, ranking among its three leading figures.