“If the EEC developed effectively as one unit, it could readily by the early 1970s be an economic (and political) unit of the same general order of magnitude in population and gross national products as the United States in the mid 1950s… Such a consolidation of West European resources would represent a major change in terms of world power. If these people wished to do so, and devoted themselves vigorously to it, they could by 1970 be carrying out a defence effort and a foreign aid effort not greatly less than that now being exerted by the United States. The effects of this on the structure of NATO and the position of the United Kingdom could well be serious. The Six, as a more or less cohesive political unit, would radically shift the balance of power within the alliance and the United Kingdom might be left in the cold in a United States/Six partnership….If we cannot come to terms with a successful EEC, the likelihood of its developing along anti-British lines will be much increased. In the event the EEC would come to exercise a considerable attraction for some non-committed countries in OEEC [sic]… In such a situation, the Americans might well throw the weight of their support behind the new grouping, with great detriment not only to our general position but also to Anglo/American relations. It thus seems reasonable to suppose that if the EEC is successful, the Six will by 1970 be developing into a very powerful economic and political unit, completely overshadowing the United Kingdom, capable (if France wishes) of exerting effective independent military and diplomatic power and probably changing the character of NATO”. Considers three futures: growth of de facto Western European federation; comparative failure of the EEC; complete failure. “It is impossible to say which of these three main possibilities is the most likely… Biggest question mark hangs over the policy of France”.
National Archives: DEFE23/67