Final answer:
Hugh Gaitskell, the leader of the Labour Party, stated that joining the EEC would be 'the end of a thousand years of history', expressing concern over the loss of British sovereignty. His comment reflects the contentious debate within the UK about European integration, a debate which continued until their admission to the EEC in 1973 and the 1975 referendum.
Step-by-step explanation:
The statement that joining the EEC would be 'the end of a thousand years of history' was made by Hugh Gaitskell. He was the leader of the Labour Party in the United Kingdom from December 1955 until his death in January 1963. His remark underscored the fears of some British citizens and politicians that joining the European Economic Community (EEC) would mean a significant loss of national sovereignty and an end to Britain's unique historical trajectory.
Britain's journey to joining the EEC was complicated, involving negotiations, vetoes by French President Charles de Gaulle, and concerns about the effects of membership on British agriculture and Commonwealth relations. It was not until 1973 that Britain, along with Denmark and Ireland, became a member of the EEC, with the further step of a referendum in 1975 confirming the UK's membership.