Here we set out the times when the UK government has held a referendum by putting a question to the British public outside of an election to resolve a single issue.
The first national referendum in the UK was in 1975 about Britain’s membership of the European Union (then known as the Common Market).
Britain had entered the EU in 1972 after a vote In Parliament in which both the Conservative and Labour Parliamentary Parties were split.
Labour argued in the 1974 general election that the entry deal that the Conservative Government had accepted was a poor one and that they would renegotiate the terms.
The Labour Party was, however, deeply divided as to whether to remain in the EU at all and, on winning the 1974 election, the Labour Prime Minister, Harold Wilson, agreed that here would be a referendum to decide this once the Government had renegotiated the terms.
A Yes vote was supported by the leadership of the three parties, although Labour Cabinet Ministers were allowed to campaign against, and by most of business.
The left of the Labour Party, some Conservatives, most trade unions and the SNP campaigned against.
The voters supported continued membership with a Yes vote of 67%.
Although to a considerable degree the result of Labour Party divisions, the referendum established a precedent that major constitutional issues should be put direct to the electorate.
The next referendum was on the creation of a Scottish Welsh Assemblies in 1979.
The rise of the Scottish Nationalist Party in the late 1960s brought the issue of Scottish independence or devolution to the fore and a Royal Commission set up to look at the issues had recommended a Scottish Parliament.
The SNP had achieved 30% of the Scottish vote in the general election of 1974 threatening Labour in many constituencies.
The Labour Government decided to propose Scottish and Welsh devolution but had difficulty getting the legislation through Parliament given Conservative opposition and divisions in the Labour Party, including among Scottish and Welsh MPs, and referendums were again proposed.
Rebel Labour MPs forced through an amendment that the assemblies would only be set up if voters supported the proposal and also if 40% of the registered electorate were in favour thus setting an almost impossibly high bar for success.
Scots voted by 51% to 48% for a Scottish Assembly but with a 63% turnout failed to cross the 40% barrier. 79% of the Welsh voted No.
Mrs Thatcher, in power from 1979 to 1990, was not interested in constitutional change and, quoting the Labour Prime Minister, Clement Attlee, called referendums ‘a device of dictators and demagogues’.
There were no referendums to approve the Single European Act or the Maastricht Treaty both of which made major changes to the nature of Britain’s membership of the EU.
The Labour Party, however, became committed to a range of constitutional changes.
The failure to create a Scottish Assembly, even though the Scots had voted for it, and the control of Scottish affairs by a Conservative Government that had hardly any Scottish MPs, led to the creation of a broad based Constitutional Convention that drew up plans for a Scottish Parliament.
Labour had also opposed the abolition of a London wide Government by the Conservatives in 1986.
By the time Labour won the 1997 election it had become established that changes in the system of government for parts of Britain needed to be endorsed in a referendum.
Referendums were not held, however, for other constitutional changes such as the introduction of a Human Rights Act and reform of the House of Lords, though Blair did promise one on entry to the Euro if Britain decided to apply to join.
The referendums held were:-
Blair had also agreed, under pressure from his Foreign Secretary, Jack Straw, who was more Eurosceptic, to a referendum on a proposal for a new EU Constitution.
The proposal was, in any case, defeated by referendums in France and the Netherlands, and was replaced by the weaker Lisbon Agreement.
Gordon Brown decided not to hold a referendum on the Agreement. David Cameron made a commitment to hold a referendum on the issue but abandoned this in 2009, while still in opposition, after all other EU countries had accepted the Treaty but promised a referendum on future changes.
This created a suspicion of what he would do on Europe among his most Eurosceptic backbenchers.
The Coalition Government held three referendums:-
A referendum in 2011 on whether the UK electoral system should change, only the second UK wide referendum.
When the Coalition Agreement was drawn up in 2010 the Liberal Democrats would have preferred to change the voting system to a proportional one but, knowing that the Conservatives, would not allow this, they agreed to a referendum on the introducing the Alternative Vote system instead.
Instead of First Past the Post, voters would put candidates in order of preference. If no candidate gained 50% of the vote, the lowest candidate would be eliminated and their second preferences distributed to the other candidates and so on until a candidate achieves 50%.
This system would probably have helped the Liberal Democrats as, where they were the main challengers in a seat, Labour voters with their candidate in third place would probably have put them as their second preference to stop a Conservative MP from being elected and the same for Conservative voters where Labour and the Liberal Democrats where the top two parties.
In return the Conservatives would be able to introduce equal size constituencies which they felt would remove the bias in the electoral system which helped Labour.
The Liberal Democrats, the Labour leadership and most of the smaller parties supported AV in the campaign arguing that it would mean that an MP would have to get majority support and so even those in safe seats would have to work harder to win people across.
The Conservatives and prominent Labour politicians campaigned against. The unpopularity of the Liberal Democrat leader, Nick Clegg, was used by the NO Campaign who were able to present the proposal as a compromise brokered by the two Coalition partners and some supporters of proportional representation were able to point out that AV could produce a less proportional result than AV under some circumstances.
The AV proposal was defeated with 67% of voters against.
Most people were clearly not convinced of the benefits of abandoning the status quo.
A referendum to give more powers to the Welsh Assembly in 2011 gained 63% support.
Pressure had grown to give the Welsh Assembly similar powers to that of the Scottish Parliament with less need for Westminster to agree changes as the original legislation had required.
A referendum was held in 2014 on Scottish independence.
The SNP had won the election for the Scottish Parliament in 2011 and had promised a referendum on independence in its manifesto.
In the 2012 Edinburgh Agreement, Cameron agreed to a vote in 2014 which gave the Yes campaign two years to organise and for 16 and 17 year olds, who were expected to be more sympathetic to independence, to vote.
The referendum campaign attracted unprecedented political interest from the electorate, especially in the later stages of the campaign, and the turnout was 84%, the highest in any election since universal suffrage was achieved in the UK.
Major issues of the implications of independence for the economy, defence, welfare and membership of the EU were discussed.
Although one opinion poll showed a majority for Yes and this led to the British party leaders promising a major extension of devolution within months, there seems to have always been a majority for No and this was confirmed, in the end, by a 55% vote.
Nevertheless the campaign has rejuvenated democratic discussion in Scotland and led to a sudden increase in support for the SNP.
In 2015 David Cameron had a majority in the House of Commons. In his manifesto for the election he had promised voters a referendum on whether the UK would remain or leave the European Union institution.
Some say this promise was given under continued pressure from Conservative backbenchers, the rise of UK Independence Party and because he genuinely expected to be back in a coalition government and not have to deliver on the promise.
Cameron promised the referendum on whether Britain should stay in the EU would take place after he had renegotiated terms with the other EU members.
The date was set for 23 June 2016. That night the UK voted to leave the European Union and ‘Brexit’ began.
