This lecture will make a claim for a new account of political change in post-war Britain: rather than a ‘neo-liberalism’ from without, I argue for an economic liberalism from within. I write into history the Whitehall opposition, and particularly the Treasury criticism, to the great techno-nationalist programmes of the post-war age: the investments in supersonic aviation and nuclear power. While the criticism was there from the beginning in the mid-1950s, only in the 1970s were the state engineers removed from positions of influence in policymaking ushering in a transformation in the nature of the British state. No longer would it aim to leapfrog the United States to global technological domination and there was a new consensus that industry, not the state, should lead government-funded R&D projects. A decivise move towards free markets thus occurred before Margaret Thatcher even became leader of the Conservative Party. This crucial shift in the ambition and nature of British politics has hardly been recognized in British history or political science in part because the disillusion with ‘high technology’ occurred in a complex and disguised way and with the propaganda and politics of the time still defining much of the existing historiography.