How accurate are the exit polls?

At 10pm on every election day, the first major indication of the result is announced. Based on 'exit polls' conducted around the country, the winners and losers are extrapolated. Can we just head to bed afterwards then, safe in the knowledge that we won't miss anything? Well, for those of us which have to get up early in the morning, the good news is that at least in recent elections, the exit polls do call it pretty accurately.

For this infographic, we've gone back through the archives to compare the exit poll projections of the last three general elections with the actual result. While the winner was called correctly on all of these occasions, the extrapolations did have varying degrees of accuracy. The most glaring of which was the 15-seat discrepancy for the victorious Conservatives in 2015. Generally though, the margin of error sits below five.

You'll also find a more simplified look at the subject, here.