Based on this swing state polling it was hard to see how Trump could forge a path to the White House. But his support base turned out in greater strength in these areas than was forecast.

Why was this the case?

It looks as though polling in these swing states failed to see just how many white working class people - the core of Trump's support - would turn out to push him over the line.

Analysis shows the the higher the proportion of lower-educated white people in a particular state, the higher the polling gap was in favour of Trump.

Non-college educated white people make up 41.2 per cent of Indiana's population, for example. The polling gap here was 8.6 percentage points - with the polls giving an average 10.7 point lead to Trump, compared to the actual 19.3 point lead he managed.

Wisconsin - a crucial state that swung to Trump to give him the last 10 electoral college votes he needed - has 35.7 per cent of its people as non-college educated white people.

There was a huge 7.4 percentage point gap between the polls and the result here: the average polling on Real Clear Politics before the vote had Clinton winning by 6.5 percentage points, when in fact Trump claimed the state by 0.9 points.