Swing in a British political context is a single figure used as an indication of the scale of voter change in a single constituency. It originated as a mathematical calculation for comparing the results of two constituencies. The term "swing" has a different meaning in Australia, which has a different voting system. See Swing (Australian politics). The term swing is used in Australia in a different sense to that employed in Britain, where the term originated (see Swing (politics). ...

Original mathematical calculation

The original mathematical construct Butler Swing is defined as the average of the Conservative % gain and Labour % loss between two elections, with the percentages being calculated on the basis of the total number of votes (including those cast for candidates other than Conservative or Labour). There is an alternative version called Steed Swing which calculates the percentages on the basis of votes cast for Conservative and Labour only. It is possible for the same election to have a Butler Swing of one sign and a Steed Swing of the other. Dr. David Butler is a Social Scientist and Psephologist. ...

As an example, if in the previous election Labour had 45%, the Conservatives 35% and the Liberal Democrats 20%, and in the new election the Conservatives had 45%, Labour had 40% and the Liberal Democrats 15%, then the Butler Swing would be the average of the Conservative gain (10%) and Labour loss (5%), which makes +7.5%.

Creation

Swing was originated by David Butler, a political science academic at Nuffield College, Oxford. In a contribution to 'The British General Election of 1945' he wrote "this measurement of 'swing', admittedly imperfect, does give us a broad idea of the movement of opinion from Conservative to Labour" and went on to compare the swings in each area of the country. The concept became important in the general elections of the 1950s when it was found that there was a relatively uniform swing across all constituencies. This made it easy to predict the final outcomes of general elections when few actual results were known, as the swing in the first constituency to declare could be applied to every seat. Taking the national vote shares in an opinion poll could also easily be translated into likely seat outcomes. Election night television programmes from 1955 have usually featured a device known as the 'swingometer' which consisted of a pendulum which could point to the swing nationally and illustrate the outcome. Dr. David Butler is a Social Scientist and Psephologist. ... Nuffield College is one of the constituent colleges of the University of Oxford in the United Kingdom. ... Peter Snow making use of a Swingometer in the BBCs coverage of the 2005 UK General Election The swingometer is a graphic device used to illustrate the shift in election results from the previous election. ...

Problems and development

During the post-war period British politics was characterised by a strong two-party system. Almost all voters who changed their preference from one election to another, swung between one of the two parties. Although the majority still do, there has a much greater variety in change since the re-emergence of three-party politics in the 1970s. The original calculation of swing did not make any allowance for other parties and when the votes for other parties rose, demands arose for a more sophisticated measurement. The continuation of the first-past-the-post electoral system, and the tendency for smaller parties to only run in some constituencies, made it increasingly difficult to use measures of swing to predict results. This article or section does not cite its references or sources. ... The first-past-the-post electoral system is a voting system for single-member districts, variously called first-past-the-post (FPTP or FPP), winner-take-all, plurality voting, or relative majority. ...

The Liberals (and, later, Liberal Democrats) have been the main catalyst for this change, providing a centrist alternative to the two parties. The situation has also changed due to the success of the SNP in Scotland and Plaid Cymru in Wales, especially in elections to the Scottish Parliament and Welsh Assembly. Two other mass parties - the Green Party, which emerged in the 1980s, and UKIP, which emerged in the 1990s - have yet to win any seats in Parliament, but have had a significant effect on the swing in certain areas, most notably when the Greens took 22% of the vote in the Brighton Pavilion constituency in the 2005 general election. The Liberal Party was one of the two major British political parties from the early 19th century until the 1920s, and a third party of varying strength and importance up to 1988, when it merged with the Social Democratic Party (the SDP) to form a new party which would become... The Liberal Democrats, often shortened to Lib Dems, are a liberal political party in the United Kingdom. ... In Scotland, the Scottish National Party (SNP) is a centre-left political party which campaigns for Scottish independence. ... Motto: Nemo me impune lacessit (English: No one provokes me with impunity) Scotlands location within Europe Scotlands location within the United Kingdom Languages English, Gaelic, Scots Capital Edinburgh Largest city Glasgow First Minister Jack McConnell Area - Total - % water Ranked 2nd UK 78,782 km² 1. ... Plaid, in full Plaid Cymru (pronounced IPA: ) – The Party of Wales, is the principal nationalist political party in Wales. ... For an explanation of often confusing terms such as Great Britain, Britain, United Kingdom, England and Wales and England, see British Isles (terminology). ... For the national legislative body up to 1707, see Parliament of Scotland. ... The National Assembly for Wales (or NAW) (Welsh: Cynulliad Cenedlaethol Cymru) was established in 1998, following a 1997 referendum in which a small majority of voters (but not the electorate) voted in favour of the Labour Governments plans for devolution. ... The Green Party of England and Wales (GPEW) is the principal Green political party in England and Wales. ... The United Kingdom Independence Party (commonly known as UKIP, pronounced you-kip) is a Eurosceptic political party that aims at British withdrawal from the European Union. ... Creation 1950 MP David Lepper Party Labour Type House of Commons County East Sussex EP constituency South East England Brighton Pavilion is a constituency represented in the House of Commons of the Parliament of the United Kingdom. ... The United Kingdom general election of 2005 was held on Thursday, 5 May 2005 and won by the Labour Party, led by Tony Blair. ...

Swing has also been complicated since the 1970s as the constituent areas of Britain have become increasingly fractured. The general sense of national unity that existed in the post-war era began to fall apart in the 1970s and broke, apparently irrevocably, during Margaret Thatcher's premiership. This has led to swings being very different in different areas - for instance, 1992 saw a swing to Labour in Scotland, but a swing to the Conservatives in the South East of England. Margaret Hilda Thatcher, Baroness Thatcher, LG, OM, PC, FRS (born 13 October 1925) was Prime Minister of the United Kingdom from 1979 to 1990. ...

At the same time, other parties began to win significant levels of representation in the House of Commons. This has led to swing often becoming a measurement of the changes in votes of the two biggest parties in the contituency in question, rather than just Labour and the Conservatives.

Simply substituting the Liberal Party for the Labour Party in the calculation provides a measure of a 'Swing between Conservative and Liberal'. However election results showed that this was not a useful predictor in seats which were being fought by these parties. It came to be used as a measure of the significance of the change of the vote. Almost all published election results are derived from the Press Association results service which in recent years shows the swing as between the two parties that came first and second, rather than strictly between Conservative and Labour. For this reason, the direction of swing is explicitly stated, rather than simply indicated through the sign as applies to Butler Swing. The Press Association is the national news agency of the United Kingdom. ...

Measurements

It should be noted that Butler Swings of over 10% in magnitude are very rare. Taking British politics after 1945 exclusively (as that election occurred ten years after its predecessor, and in a completely different political climate), only the 1997 general election had a national swing of more than 10% in magnitude, and that was -10.23%. The table below shows the national swing across Great Britain, and the number of individual constituencies out of more than 600 which had a swing of over 10% in magnitude. Clement Attlee Winston Churchill The United Kingdom General Election of 1945 held on 5 July 1945 but not counted and declared until 26 July 1945 (due to the time it took to transport the votes of those serving overseas) was one of the most significant general elections of the 20th... The UK general election, 1997 was held on 1 May 1997. ...

Conventional swing is much more volatile, and many more constituencies have large conventional swings. In addition, the conventional swing in a constituency where the top two candidates are not Conservative and Labour cannot be meaningfully compared with the national or regional swing. The 1951 election was held soon after the UK general election, 1950, which Labour won, but with an unworkable majority. ... The 1955 United Kingdom general election was held on May 26, 1955, four years after the previous general election. ... This United Kingdom general election was held on October 8, 1959, and marked a third successive victory for the ruling Conservative party, led by Harold MacMillan. ... The United Kingdom general election of 1964 result was a very slim majority for the Labour Party, of 4, and led to their first government since 1951. ... The UK general election in 1966 was called by Harold Wilson because his government, elected in the 1964 election, had an unworkably small majority. ... The United Kingdom general election of 1970 was held on June 18, 1970, and resulted in a surprise loss of power for Labour under Harold Wilson, who was replaced as Prime Minister by the Conservative leader, Edward Heath. ... The UK general election of February 1974 was held on February 28, 1974. ... The UK general election of October 1974 took place on October 10, 1974. ... Margaret Thatcher James Callaghan David Steel The UK general election, 1979 was held on May 3, 1979 and is regarded as a pivotal point in 20th century British politics. ... The UK general election, 1983 was held on June 9, 1983 and gave the Conservatives and Margaret Thatcher the most decisive election victory since that of Labour in 1945. ... The UK general election, 1987 was held on June 11, 1987 and was the third victory in a row for Margaret Thatcher and the Conservatives. ... The UK general election, 1992 was held on April 9, 1992, and was the fourth victory in a row for the Conservatives. ... The UK general election, 1997 was held on 1 May 1997. ... The UK general election, 2001 was held on 7 June 2001 and was dubbed the quiet landslide by the media. ... The United Kingdom general election of 2005 was held on Thursday, 5 May 2005 and won by the Labour Party, led by Tony Blair. ...

References

• The British General Election of 1945 by R.B. McCallum and Alison Readman (Oxford University Press, 1947) pages 263-5
• Political Change in Britain by David Butler and Donald Stokes (Macmillan, 1969) pages 140-51