The Johnson-Corbyn debate today will be the first ‘head-to-head’ leaders’ debate between the two main parties in UK political history.
We have had variations on the theme before: the 2010 outing between Gordon Brown, David Cameron and Nick Clegg; a debate among all the opposition parties in 2015; the three-on-three battle at Wembley during the 2016 referendum; and the debates in 2017, where all the party leaders apart from Theresa May turned up.
Various claims have been made by those involved in the debates before: who watches them, what difference they make and what impact they can have.
‘It’s hard to recover from a bad first outing’
This was the advice in 2012 of the US campaign strategist Brett O’Donnell who, in what is becoming a time-honoured tradition, has been flown over by the Conservatives to offer American advice on what is still a novel feature of British politics.
The evidence from history tells us he could be right: in 2010, the first debate – as today, on ITV and some three weeks out from polling day – was the most viewed and undoubtedly the most impactful.
According to the British Election Study (BES), some 61% of the public said they’d seen or heard at least some of that debate, which gave rise to ‘Cleggmania’.
This compares to 45% who saw or heard at least part of the second debate on Sky, and 51% who saw the third debate on the BBC.
‘Being unknown to so many people, prior to the 2010 election, gave me the advantage of surprise in the TV debates’
Nick Clegg argued that his anonymity prior to the debates was his greatest strength in the 2010 general election.
David Cameron, widely seen as favourite in the run-up to those debates, has a different analysis of what went wrong. He argues that the debate format ‘gives an artificial leg-up to the underdog’.
Whether it’s important to come from behind or be a surprise package also matters this time.
Jeremy Corbyn is certainly not unknown, as the first opposition leader to fight a second election since Neil Kinnock in 1992.
Johnson and Corbyn are the first and second most well-known politicians in the UK. As a result, voters already have strong impressions of both.
When compared to 2010, it is clear there was one big difference between the leaders: people had a view on Brown and Cameron, but had no strong view at all on Nick Clegg.
This time (using figures drawn from the latest BES waves in March and June) voters have a fairly strong view of both leaders.
Jeremy Corbyn will be hoping that Cameron is right, and that his underdog status is what makes the difference.
Yet it is also clear is that both look set to profit from the absence of Lib Dem leader Jo Swinson, whose inclusion in the debates would introduce her to many voters for the first time. Swinsationalism may not therefore sweep the country like Cleggmania before it.
‘A few had watched the ITV debate, but it hadn’t enlightened them in any way. … This is consistent with undecided/persuadable voters’
This view, from a focus group in Durham conducted by the Remain campaign in the 2016 referendum, speaks to a key question: who are the people that are listening to the debates, and are they the sort of people likely to change their minds?
Obviously, switching on the TV at 8pm rather than watching Netflix is itself a self-selecting process. Finding politics clips online afterwards also makes you a certain type of person.
This could well be exacerbated by voter fatigue: there is little novelty this time around unlike in the first debates in 2010 and the referendum in 2016.
Different parts of the UK might also be turned off: it’s far from certain voters in Scotland – just as likely to watch the debates as people in other parts of the UK in 2010 – will still be watching given the absence of Nicola Sturgeon.
And, in the 2010 general election, if you said you’d seen or heard some or all of the debates you were – on average – more likely to be somebody in favour of the European Union.
Some 67% of those who approved of the EU watched the first debate, against 58% who disapproved – making you substantially more likely to watch if you supported membership.
This is likely a function of demographic factors, such as age, income and education, that drive connectedness to the news cycle.
However, it perhaps suggests a problem for Boris Johnson (and, indeed, potentially for Jeremy Corbyn): if history is any guide, those who end up seeing the debate are people who are more likely to be against Brexit.
This should perhaps give some pause for thought for all those feverishly overinterpreting the debate this evening: those watching won’t be quite the same as those voting in a few weeks’ time.
Just as important as the debate itself may be the post-debate spin and social media aftershocks.