These diaries are of a parliamentarian devoted to the cause of parliamentary sovereignty. Sir Neil Marten was a soldier, spy, politician, husband, father, and grandfather. The First Brexiteer provides an incredible insight into the worlds of politics and Parliament during the tumultuous Heath administration and the early Thatcher years in opposition. The Heath years were dominated by two issues that haunted the country for some considerable time. The first, for which Marten was best known, was the battle over Britain's entry to the EEC. The second was Heath's policy U-turns from which Thatcherism sprang. Neil Marten was Britain's first Brexiteer. He organised the most determined parliamentary campaign oppose Britain's entry to the EEC, chaired the 'No' campaign in the 1975 referendum to leave the EEC, and continued agitation in parliament against ever closer European union. Without his activism the Eurosceptic movement would have had significantly weaker foundations. These pages reveal his contribution to British politics and to his country.