Sidney is widely acknowledged as a ‘leader’ of Manchester’s Jewish communities from the 1960s. Following in the footsteps of Nathan Laski and Abraham Moss, he became an acknowledged spokesman for Manchester’s Jews. His preference was for unity, centralisation and co-ordination. He worked, in the most part, through two organisations – the Jewish Representative Council of Greater Manchester (of which he became president in 1960) and the Zionist Central Council (president from 1963). Sidney saw himself as an agency of radical change to some 200 existing community organisations which by the 1940s were no longer representative of the Jewish communities in Manchester.