The opinion polls: some historic context

One week out from polling day in the general election, how do the opinion polls compare with previous general elections?

Looking at the opinion polls published on the Thursday and Friday before polling day in previous general elections, the picture for Labour is uncomfortable. In 1997 the polls gave them between 48% and 50% (result: 44%), in 2001 43-48% (result: 42%) and in 2005 36-40% (result 36%). In other words, Labour have consistently polled at or below the spread of poll results a week out. This time round the spread is 27-29%, bracketing their 1983 low point and a share that would most likely put the party third.

For the Conservatives the situation is better, though not all good. In 1997 the spread was 27-32% (result: 31%), in 2001 30-31% (result: 33%) and in 2005 31-33% (result: 33%). Not quite so neat a pattern as for Labour, but the Conservative pattern is to poll at or slightly better than the best poll results a week out. This time the Tories are on 34-36%. That is significantly short of the sort of vote share that will probably be needed to win an overall majority. But it is the sort of share that, combined with Labour in the high twenties, would most likely make the Conservatives the largest party.

For the Liberal Democrats, history shows a pattern is of polling at the top end of the poll results a week out. In 1997 the party scored 17% (poll spread a week out was 12%-17%), in 2001 19% (16-19%) and in 2005 23% (20-24%). This time the spread is 26-31%. If the pattern is repeated, that would put the Liberal Democrats in second in the share of the vote and almost certainly see the party have significant influence in a Parliament where no one party has an overall majority.

History of course keeps us on our toes by never quite repeating exactly – and this time there is still the impact of the third party leaders’ debate to digest as well as the unfolding dynamic of an election race that is seen to be far closer than any of the last three.