In 1992 – the last time a Conservative Prime Minister called a general election – the campaign lasted just 30 days, from John Major asking the Queen to dissolve Parliament on 11 March to voters going to the polls on 9 April. By contrast the 2015 election campaign will last 1,330 days (roughly three and a half years).
Effectively, the starting pistol for the 2015 general election was fired on 15 September 2011 when the Fixed Term Parliaments Act received its royal assent. This single piece of legislation – one of the Lib Dem’s only constitutional reforms to make it into law – removed the Prime Minister’s power to call a general election before the end of a Parliament’s five year term of office. In doing so, it re-wrote the UK’s political play book, changed how and when the major parties launch new policies and transformed general election campaigns from short, intense contests into protracted, grinding wars of attrition.
The 2011 Act set in stone the date when the next general election would be held – 7 May 2015. This date could only be changed if one of two events occurred: a majority of the House of Commons voted against the Government on a motion of no confidence, or if two-thirds of MPs vote in favour of an early election. The Coalition makes the first of these scenarios unlikely and parliamentary arithmetic makes the second almost impossible.
Whilst a seemingly endless election campaign is likely to irritate the electorate, a basic statistical analysis of full-term Parliaments casts its own foreboding shadow over David Cameron.
Prior to the 2011 Act, Prime Ministers used to be able to call snap elections when they expected their party would benefit, adding an element of unpredictability to politics. Parliaments lasting for their full five year duration were very much a rarity. Only three of the 17 Parliaments elected between 1945 and 2010 lasted for a full 5 years . In each of these three occasions (1959-64, 1992-97, and 2005-10), the five-year Parliament proved to be the last term in power for an incumbent party that had held power for long period of office already (thirteen, eighteen and thirteen years respectively). The fact that incumbent parties tend to lose elections held after full term Parliaments explains why they are such a rarity. Turkeys don’t vote for Christmas.
If anything, the widely held expectation was that the 2010 Parliament would not only fail to last 5 years, but would probably end much, much sooner than that. A governing party that either lacked a majority or only had a slender (usually single digit) majority would historically to go back to the people very quickly to try and secure a more workable majority. That has been the case with all three of the post-war Parliaments that lasted less than three years (1950-51, 1964-66 and Feb-Oct 1974). In two of these three cases – 1966 and October 1974 – the governing party gained seats and retained office.
For a Prime Minister wishing to remain in office, the optimum time to call an election would seem to be more three-and-a-half years into the Parliament, but short of the full five year term. Of the 11 post-war elections called within this ‘window of opportunity’, eight have seen the governing party returned.
On 7 May 2015 David Cameron will not just face the judgement of the electorate, he will be challenging the lessons of political history. And, if he loses, it may well be the result of a seemingly inconsequential law that his own Government put on the statute book.
 – Eagle-eyed readers will note the omission of the 1987-92 Parliament. In fact, the 1992 general election was held in April 1992, almost four months before the official end of that Parliament’s full five year term.
James Ford is a Senior Adviser at PLMR. Previously he was an aide to Mayor of London Boris Johnson, advising him on transport, digital and environment policy between 2010 and 2012.