A referendum is the procedure by which a decision is referred to the electorate who vote on it in a similar way to a general election. The only two referendums to date in the whole of the UK were in 2011 and 1975. In 2011 the referendum was about whether the UK should change to the Alternative Vote system of voting from the First Past the Post system for general elections. In 1975 there was a referendum on whether the UK should remain a member of the Common Market (now the European Union).
Referendums were held in Scotland and Wales in 1979 and again in 1997 on devolution; in Northern Ireland in 1973 and 1998 on the Province's constitutional future; and in Greater London in 1998.