From the time of his retirement until his death in 1948 Reilly's concern with town planning issues was to find new impetus, further increased during the latter years of the Second World War when it became apparent that many of Britain's towns and cities would need massive rebuilding following wartime bomb damage. Reilly's credentials as a commentator on such matters were impeccable: he was one of the founding fathers of urban planning; he had had a leading role in the establishment of the world's first university department of civic design; and he had close associations with such planning luminaries as Adshead, Abercrombie, and his former student William Holford, who was a rising star. Reilly was every newspaper editor's first choice when they required an authoritative commentator on contentious planning issues. Myles Wright considered that Reilly's stance on planning ideology changed little from 1909 onwards, when he had helped William Lever to set up the Department of Civic Design at Liverpool University. This is both right and wrong, for although Reilly remained committed to ‘civic’ (essentially urban) planning, his ideas were inevitably modified both by the influence of dedicated planners such as Abercrombie, and his own gradual shift in stylistic allegiance from the grandiose Beaux-Arts vistas of his earlier conceptions, to the Modernist, ‘organic’ community planning of his Reilly Greens.

The origins of Reilly's reassessments of town planning theory can be traced back to a number of possible sources. Following the Wall Street Crash of 1929 the Liverpool School of Architecture found it increasingly difficult to place the same number of students in American practices as had been the case throughout the 1920s. Alternative sources of practical training were sought, and a number of his most able students took work placements in municipal authorities and government departments around the country. Although less glamorous than a New York placement, such work experience exposed students to the new developments in social housing taking place in a number of local authority architecture departments at that time, not least in Liverpool where the Corporation Director of Housing, Lancelot Keay, was overseeing a major public housing programme.