What can we expect over the next six months? Ian Jones charts the changes of every election since 1987.

Photo: Getty

By Ian Jones

We’ve hit another milestone in the countdown to the general election.

The fact we know there are now precisely six months until polling day has robbed the event of a little of its drama. The element of surprise has disappeared, along with an uncertainty over timetables and procedures that used to keep both candidates and pundits on their toes.

In their place we have the certainty of knowing exactly when the UK will next go to the polls, and the temptation to make all sorts of predictions based on what may or may not happen between now and then.

Knowing exactly where we are in the life of this parliament means we can compare the present with the past. Does history suggest voters have more or less made up their minds half a year out from an election – or can things still change, and to what extent?

To make my comparisons I’ve used the Nuffield studies of every British election and the polling data that May2015 host, which goes back to 1970. I’ve used an average of the two or three polls published around six months before the election.

2010

Remember when parties used to get 40 per cent in the polls? That’s what the Tories were enjoying six months before the 2010 election. What happened next turned a likely Tory majority government into a hung parliament:

The Conservatives shed four points, Labour gained two and the Lib Dems rose by six. Half a year out the polls didn’t anticipate the tightening of the race.

2010 was unusual in recent history for the way all three parties experienced significant movement in the polls in the months before polling day. Things were very different five years earlier.

2005

Here the polls were almost spot on six months ahead of polling day. The Tories stood at 32 per cent and Labour at 35 per cent. Both of these figures would be repeated at the election:

Only the Lib Dems’ share of the vote changed – but that was only by one point. 2005 represents the most static of my six historical comparisons.

2001

Labour’s share of the vote fell by five points in the months leading up to polling day in 2001. At most elections this would have been cause for concern, but here the party’s lead was so big to begin with that such a drop proved of little consequence:

Notice that the Tories even managed to slip back a point as well. Only the Lib Dems improved their share. 2001 was a rare recent example of both the two biggest parties losing support in the run-up to an election.

1997

For fans of conventional two-party politics, it’s rather poignant to be reminded of a time when one party alone was able to command over 50 per cent of the vote in an opinion poll:

Labour averaged a massive 52 per cent six months ahead of the 1997 election. This figure proceeded to fall by nine points, but still delivered a landslide. The Tories’ average remained stuck on 31 per cent, while the Lib Dems – as had become the trend – picked up a few points.

1992

Here’s the odd one out in my half dozen historical snapshots. Labour went from having a four-point lead over the Tories six months before the 1992 election to being eight points behind on polling day. It was a sensational turnaround, and one famously missed by almost every opinion poll at the time:

The Tories’ share went up by only two points, but that was enough to deliver them a majority government. It’s a mark of our changing times that Labour would probably be quite happy with 34 per cent at the 2015 election – so long as the Tories were a couple of points behind.

1987

Labour suffered another pre-election slump in 1987, but this time from a position of forcing a hung parliament to one of allowing a third term in office for Margaret Thatcher’s government.

There was never really a doubt that the Tories would emerge as the largest party at this election. The question was whether the result would be a close or, as proved to be the case, another landslide:

1987 was the second and last election to feature the SDP/Liberal Alliance, and despite polling 23 per cent on election day they ended up with less than half the number of seats the Lib Dems won on just 18 per cent in 2001. The public would take another decade or so to wise up to tactical voting.

In conclusion

Recent history suggests that while polls do move in the six months before an election, the winner tends to be already clear. 1992 aside, in every scenario over the past 30 years the party in front six months before an election was still in front on the big day. With the two major parties now tied in the polls, that precedent is limited.

It is not the case that an incumbent government always improves its poll rating as an election nears. The Tories did in 1987 and 1992, but Labour did not in 2001 or 2005.

Whether these patterns still apply depends largely on whether you think the polls will move a great amount between now and 7 May 2015. I tend to think they won’t.

What I do think is that we’ll continue to see movement of a small amount. And with Labour and the Tories as close as they have been since 1992, even a tiny change could affect the chances of either party. 22 years on, John Major’s defeat of Neil Kinnock should continue to haunt the calculations of both pollsters and politicians.

Ian Jones runs ukgeneralelection.com. Follow his work for daily doses of number-crunching, news-spotting and result-pondering.