By Josh Eldridge, Consultant, London

Marginal seats are where elections are won and lost. These electoral battlegrounds are crucial for determining the ‘swing’ necessary for a change in government and always attract the most attention. However, it is important to note that the vast majority of parliamentary constituencies do not change hands. Many areas possess strong political identities forged along economic or cultural lines that mean traditional party allegiances are hard to break. This is re-enforced by opposition parties not putting full energy into winning such seats, with candidates aware they have little chance of success. Consequently, parties divert campaign funding away from these areas to focus resources on the marginal seats with the highest prevalence of swing voters.

So what constitutes a marginal seat? A marginal seat refers to a seat without a comfortable majority i.e. the opposite of a safe seat. In the absence of a set figure defining when a seat is or isn’t marginal, it may be helpful to consider all seats with a majority of less than 10% as marginal. Using this particular barometer of marginality, there are 194 marginal seats in Britain. 82 of these are currently held by the Conservative Party, with 79 belonging to Labour and 27 to the Liberal Democrats (almost half of their total seats). The statistical spread of seats amongst the parties is key as it indicates the focus of the parties’ respective strategies. For instance the Conservatives are employing a ‘40/40’ strategy, having selected 40 key seats to hold and gain respectively, whilst the Lib Dems are treating the defence of all their 57 seats as individual by-elections.

The Conservative’s most marginal seat is Warwickshire North, currently held by Dan Byles MP. Byles snatched the seat from former Labour Minister Mike O’Brien in 2010 by just 54 votes, making it the second smallest parliamentary majority in Britain. Ousting O’Brien after 18 years at the reigns was a major achievement, but Byles joins the ranks of 2010 Tories who will not be standing for re-election in in May, leaving the defence of the Conservative’s slimmest majority to newcomer Craig Tracey.

Labour’s most marginal seat, Hampstead and Kilburn, also holds the dubious accolade of being the most marginal seat in Britain, possessing a majority of just 42. Prior to electoral boundary change in 2010, Glenda Jackson MP had enjoyed reasonably good majorities over the course of her long parliamentary career. However, when boundaries changed, so did voting behaviour; so much so that in 2010 Hampstead and Kilburn also became the closest three-way marginal seat in the 2010 Parliament, as the third-placed candidate obtained just 841 fewer votes than the winner. Indeed, the Green and UKIP candidates secured 1100 votes between them last time in that part of North London, votes that could have been used to determine a different winner. Such close three-way contests are rare but will become more common as the minor parties wrestle vote share away from Labour and the Conservatives.

Voters in marginal seats tend to be more engaged than those in safe seats and historic turnout statistics support this claim. In every UK election since 1950, turnout has been higher in marginal seats than the average national turnout, further justifying the increased spending evidenced in such seats. Some seats have a history of being marginal and always return an MP from the winning party. Dartford is the best example of these co-called ‘bellwether seats’, having returned an MP from the party that went on to win the election since 1964.

An examination of the prevalence and regional distribution of marginal seats can benefit electoral predictions, but should not be looked at in isolation. For instance, an analysis of Scottish marginal seats would be unlikely to produce accurate predictions. Whilst the SNP are expected to take a number of seats from Labour in Scotland, 2010 election data suggests that there aren’t any Labour/SNP marginal seats, clearly not reflecting the recent surge in SNP support.  However, in the total absence of certainty regarding the outcome of #GE2015, eager election spectators are advised to focus their attention on the relatively small number of marginal seats that will ultimately decide the composition of the next Government.

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