As with guests who have outstayed their welcome, a question increasingly asked about postwar controls was, when would they be gone? The immediate postwar presumption that they were merely short-term measures to ease the reconversion from a wartime economy had tended to discourage any wider philosophical discussion of the duration and extent of controls. As Ronnie Tress noted in June 1947, there seemed to be a reasonably wide assumption in the civil service that ‘the controls are just to tide us over the transition period and we must use what machinery we have, we can't have any new controls and it isn't worthwhile rationalising the whole construction’. When, in 1947, persistent excess demand and balance-of-payments problems prompted fundamental changes in the structure of economic planning, there was an associated increase in discussion of the purpose and philosophy of planning. It was then, while working on the draft Economic Plan, that Edwin Plowden turned to Alec Cairncross and asked ‘the question which has been troubling all of us for some time. What is the general philosophy behind the Plan? What is it we are trying to do and what system of controls is needed to do it?’ The subsequent debates within Whitehall between Hall, Cairncross, Gaitskell, Meade, Robinson, and others were complemented by discussion in other fora such as the 24th Nuffield private conference on ‘The Government's Controls of Industry and Trade’ on 26–7 June 1948 attended by academics, civil servants and industrialists.