Monday sees the kick-off to the first full week of the UK’s sole pre-Christmas general election since 1923. While Boris Johnson pushed hard for the ballot to go ahead before the New Year, it is a huge gamble and could easily backfire given the exceptional unpredictability of contemporary UK politics.

The start of the campaign comes as Johnson’s promise to leave the EU by October 31, “do or die”, has vaporised. Part of his goal in calling the election is therefore to deflect this political embarrassment by seeking to act decisively, and in turn trying to head off a challenge from the hard-line Brexit Party for the allegiances of the bloc of 2016 referendum ‘Leave’ voters.

Johnson’s decision represents a massive ‘roll of the dice’ on at least two levels. And to this end, the Cabinet was reportedly deeply split last week over the wisdom of his decision remembering the way that Theresa May’s big polling lead in 2017 almost went into reverse during a see-saw campaign.

Firstly, there is a good reason why UK governments have not for almost a century held a December election. That is, in large part, due to the winter weather which will probably depress turnout, bringing further unpredictability to the poll outcome if it goes ahead.

A second level of uncertainty is well documented in new data from the British Election Study (BES) released last month. That is, the currently unprecedented UK voter volatility right now stemming from a series of “electoral shocks” from Brexit to the aftermath of the 2008-09 international financial crisis.

‘Shock’ factor

The BES, which is perhaps the most authoritative survey of UK voting behaviour, indicates how much voters are increasingly influenced by such key “shocks” that at least potentially realign the political landscape. And given this fluidity, traditional partisan voting patterns are eroding faster.

Take the example of the UK’s 2015 and 2017 General Elections which saw more people change their vote than ever before in the post-war era. Remarkably, nearly half the country (49%) voting for different parties across the three elections from 2010-17 according to BES.

A key reason behind this is the erosion of the classical left-right dichotomy in distinguishing Conservative from Labour voters. Indeed, the BES study asserts that, for the first time in modern UK history, the 2017 election saw issues including immigration and Europe/ EU at least equally as important in determining overall voting behaviour as traditional right-left party allegiances.

In 2017, there was therefore the highest levels of switching between the Conservatives and Labour since the BES started its research in 1964. This phenomenon was driven by Brexit with Labour winning the support of 31% of previous Tory voters because of its more pro-EU stance, and the Conservatives winning the loyalties of significant numbers of pro-Leave former Labour supporters.

Johnson’s election game plan for December 12 is to frame the election around Brexit, as was May’s in 2017. He perceives his best opportunity to try to outflank opposition parties with a claim to being the competent leadership to oversee the UK’s planned departure from the EU.

Yet, this strategy could easily backfire if much of the electorate does not share his assumptions on Brexit, or sees the ballot through a wider prism of issues such as the economy, the National Health Service, and/ or ‘law and order’. Were this to happen, as the Opposition Labour Party will encourage, Johnson will not be able to fight on his chosen terrain, as was May’s Achilles heel in 2017.

And there is also the possibility, in a several week campaign, that Johnson may make a series of gaffes under pressure. While he appears to be a significantly more natural national campaigner than May, he remains untested in the intensity of a general election.

If the issues shift beyond Brexit, the prime minister will have been relieved by the fact that the House of Commons last month backed the government’s Queen’s Speech by a majority of 16. This is the forward-looking programme of legislative that Johnson team would look to implement in coming years with key themes including health, education, transport and crime.

The reason why Labour, however, would like the election terrain to focus on this wider agenda is the back story of significant public sector cuts that have taken place since the international financial crisis. On law and order, for instance the party has pledged re-recruitment of around 20,000 police officer positions, an agenda Johnson now appears to share too.

It is in this cauldron of uncertainty that the forthcoming election will be fought. The ballot is far from straight forward to forecast with Johnson potentially proving to be its victim rather than beneficiary, as was the case for May in 2017.

—Andrew Hammond is an Associate at LSE IDEAS at the London School of Economics.