Focusing on the shift from coal to oil in the French and British economies between 1945 and 1972, this article analyses the influence of economists and economic concepts on fuel-policy making in each economy. The framing of French fuel policy around marginalist principles from 1958 is examined, and the unusually direct influence of economists on policy making is ascribed to a mix of national security, industrial modernization, and political considerations.he emergence of coal surpluses in most western European economies by 1958 signalled both an end to the post-Second World War coal shortages and confronted national governments with the major issue of deciding the future bases of national fuel policy. In Britain and France, discussion of the particular issue of the balance to be struck between oil imports and domestically produced coal was conducted using contrasting political and economic conceptual approaches and vocabulary. In Britain the dominant expression of concern to minimize the unemployment arising from the managed contraction of the coal-mining industry contrasted with the explicitly marginalist economic approach to the issue adopted in France. In both countries, leading economists were to argue for a marginalist approach towards the making of national fuel policy. James Meade and Ian Little were perhaps the best-known examples in Britain, with Maurice Allais and Marcel Boiteux as their proximate counterparts. 2 Yet where Meade and Little were forced into the wings of government fuel-policy making, from 1958 Allais and Boiteux were invited centre stage. Analysing the extent and causes of this apparent difference in the use of the marginalist concept in each country is the central concern of this article, a close study of fuelpolicy making being used as the basis both for examining the process whereby economic concepts are translated into policy and outcomes, and 1 I would like to thank three anonymous referees and J. P. Bonaïti for their comments on an earlier version of this article. Any errors of fact and judgement remain my responsibility.2 Allais, Aspects essentiels; Allais, Gestion des houillères ; Boiteux, 'Tarification des demandes en pointe'; Little, Price of fuel; Meade and Fleming, 'Price and output policy'. T