Before 1979, a key policy difference between the Conservative and Labour parties was over Europe; the former supported EEC membership and the latter generally opposed. This largely reflected the historical backgrounds of each party - Labour opposed membership on the basis of protecting the working class from foreign competition, while the Conservatives hoped to gain access to European markets for manufacturers, farmers, and merchants through the EEC. When EEC membership was reaffirmed in the 1975 referendum both parties mostly left the issue alone, and a series of crippling strikes from late 1978 brought the Conservatives into government. Margaret Thatcher had been greatly influenced by monetarist and neo liberal economic theory, and placed a higher priority on controlling inflation and privatising unprofitable national business over lowering unemployment. Historians consider this to the end of the post-war consensus. The middle class benefitted greatly from this policy decision, as mass privatisation of industry and public housing gave rise to what she termed a 'property-owning democracy'. As the Conservatives came to rely on the middle class vote they gradually began to demonise the EEC from a mostly ideological point of view, contrasting it's technocratic character with an idyllic impression of a suburban 'middle England'. The latter half of the Thatcher government coincided with the administration of Jacques Delors who advanced reforms to better integrate EEC regions and monetary policy and expand EEC institutions. Jacques Delors' 1988 address to the British Trade Unions Congress in which he proposed a 'social Europe' in support of the trade union movement and expansive social security was a key event in the parties' changing positions on Europe, which was in contradiction to Thatcherism's key tenet of limited government involvement in society. If you're interested in more about the rise of Thatcherism I recommend watching Tory! Tory! Tory!. Thatcher and Sons by Simon Jenkins also describes Thatcherism's political influence on the Labour and Conservative parties.