Sidney’s impact, however, extended beyond Manchester’s Jewish communities. In 1946 he was elected to Salford City Council under the Labour interest. As chairman of the Planning and Finance Committees of Salford City Council between 1949 and 1967, he played a central role in post-war construction of the city. He was also the first chairman of the North Western Regional Health Authority between 1973 and 1982, which was critical in the transformation of British public health administration, and mayor of Salford from 1968 to 1969.