A direct vote in which an entire electorate is invited to vote on a particular proposal. In the UK, referendums are normally advisory in law, since parliament remains sovereign, but their results are treated as politically binding. They have been used mainly for major constitutional questions, including EEC membership (1975), devolution (1979, 1997, 2011), the Good Friday Agreement (1998), the voting system (2011), Scottish independence (2014) and EU membership (2016).