ABOUT 10 SECONDS after 10 pm on the evening of 8 June 2017, Theresa May and the rest of the UK knew she’d made a mistake in calling a snap general election.
The BBC’s David Dimbleby delivered the results of the exit poll, declaring that May’s party would lose about 17 seats and its majority in parliament.
“The Prime Minister called this election because she wanted certainty and stability, it doesn’t look at this stage that she’s got certainty and stability,” Dimbleby said.
Anyone watching the coverage that night will remember reporters quoting senior Conservatives who were flatly disputing the figures.
That was until the results starting coming in and the exit poll was proven to be more or less accurate, giving the Tories only three fewer seats than they ultimately won.
The moment the exit poll is released is usually a bigger event that any in the actual counting process, Such is the comparative simplicity of the UK electoral system, the
The first-past-the-post system favours the poll winner to such a degree that, when the exit poll comes out, we usually get to know identity of the British prime minister and how strong their position is.
Exit polls are of course still a big deal in Ireland, but with transfers such a part of the PR-STV system there is much counting to be done before an accurate picture emerges.
Unencumbered with such concerns in the UK, the dramatic release of the exit poll at 10pm has become something of a recurring iconic moment in British politics.
To add to the drama, the exit poll is always prefixed by the tolling of bells and an image of Big Ben.
The exit poll was formerly exclusive to the BBC but ITV joined in 2005 and then Sky in 2010. All three broadcasters deliver their own interpretations of the same data with Ipsos MORI the polling company behind it.
How do exit polls work?
Exit polls are seen as more accurate than other pre-election polls because they’re designed to measure how people voted rather than how they intend to vote.
In the case of the UK exit poll, there are pollsters at 140 polling stations around the country and they catch people coming out after they voted.
The idea is to get a random sample, with pollsters grabbing every 15th or so person that comes out, in an attempt to eliminate any unconscious bias.
A solid exit poll will be based on about 25,000 responses, working out at about 180 people at each polling station. In 2017 the exit poll was based on 30,000 responses.
Instead of a face to face interview, voters are given a sample ballot paper and are asked to fill it out in the same way they did in the polling station.
Voters put their responses into ballot boxes which are then collected by the polling company throughout the day. It means it’s a confidential and private process, hopefully leading to more accurate results.
Pollsters can keep an eye on developing trends throughout the busy day, building up a better picture before the final numbers are crunched ahead of the 10 pm deadline.
It used to be the case that UK exit polls focused on marginal seats because of the belief was that this was where elections were won and lost, but that has changed somewhat in recent years.
This is partly because seats considered marginal may change from election to election but it’s also because much of the emphasis is about identifying changing trends.
To do this, pollsters can compare exit poll results to previous elections to see which way the winds are blowing.
Speaking on ITV’s Calling Peston podcast last week, Professor Colin Rallings of the University of Plymouth spoke about his involvement in the exit polls over the past eight elections, explaining how the methodology has changed.
“What we do is we go to places where we’ve been before. So the important thing is not so much how marginals are behaving. But how are those people that we interviewed or people in the same areas that we interviewed two years ago or four years ago.
How are they behaving this time, in exactly the same polling stations, in exactly the same towns and villages as we’re at two years ago, 2017 the last time. What’s the difference between how they’re behaving today on election day, and how they did last time, and in that way, we can look at changes for the various parties and from that we try to project how many seats each party is going to win.
Rallings also explained that some traditional beliefs and stereotypes about voting were busted in 2017.
These included the idea that Labour voters tend to vote later in the day after work while older Conservative voters may be free to vote earlier in the day. In 2017, Rallings said voter patterns were quite consistent throughout polling day.
He also revealed that the final numbers aren’t really prepared until about 20 mins before the poll is broadcast, such is the tight schedule the pollsters are working to.
“Because these things are market sensitive, of course, these days very market sensitive in a way that they weren’t 30 years ago.
A small number of people are told because graphics need to be prepared and the presenters needs to know. Although there is one well-known TV presenter who doesn’t like to know in advance of going on air at 10pm and reacts accordingly.
Exit polls through the decades
Aside from the 2017 exit poll moment, there have been others that have become iconic too.
The announcement of Tony Blair’s breakthrough win in 1997 for Labour was delivered again by Dimbleby with the simple summary: “Tony Blair is to be Prime Minister, landslide is likely.”
“Another Labour landslide,” was the prediction four years later when Blair was returned.
The 2015 exit poll caught everyone by surprise because it correctly predicted that the Conservatives would win a majority in parliament.
This came after weeks of polling had predicted a hung parliament with no clear winner.
Such was the shock at the exit poll result that Liberal Democrat former leader Paddy Ashdown famously said that the will “publicly eat my hat” if it was right.
The exit poll accurately predicted that Ashdown’s party was on course to lose nearly 50 seats after five years of coalition government with the Conservatives.
“You can get the hat, provided it’s made of marzipan,” Ashdown joked to the BBC’s Andrew Neil.
To embed this post, copy the code below on your site
have your say