Populus Perspective

In this issue

• Tilted battleground?
• Climate change on climate change?
• Going to the dogs?
• Win for the Gipper
• It's all in the question
• More Liberal Parliament?

Tilted battleground?

There is now less than three months to go before the presumed general election date of May 6th. The polls have continued to show a slight rise in Labour support - mainly coming from the fringe parties; the proportion of people who voted Labour in 2005 who now say they would vote Conservative has remained steady, at about 12% for the past year or more.

Labour have got back to about 30%, from their trough of 23% last May. But the Conservatives remain 9% ahead in the average of published polls - and all the available evidence indicates that the swing is larger in the key marginal seats than it is nationally.

No party has ever lost a poll lead of remotely that size held this close to an election. Of elections in living memory the one that the current poll position most resembles is 1987, when the Conservatives had an 11% margin over Labour that produced a Commons majority of 102; ordinarily we should be at this stage be able confidently to predict a clear Conservative victory.

The fact that the election is instead widely viewed as too close to call is, of course, because of the bias in the electoral system.

The standard rule of thumb is that, other things being equal, on a uniform national swing (i.e. one in which the same swing from Labour to Conservative occurs in every constituency) the Conservatives need to be about 11% ahead of Labour in terms of vote share in order to get an overall majority of just 1 in the House of Commons. On that basis most of the recent published polls indicate the prospect of a hung Parliament.

We can, however, say with certainty that a) other things won't be equal, and b) the swing will not be uniform. There will be numerous variables that will together determine the result - including the effectiveness of each party's targeting, regional factors, differential turnout, tactical voting and, perhaps, anti-incumbency (in the latest Populus poll nearly a third of voters say they will vote against an MP who has had to repay expenses, regardless of any other factors). By some analysis the Conservatives could win a clear majority with a national vote share lead of 'only' 5%. But we won't know until after the fact what the required margin actually was. An overall Labour majority looks extremely unlikely, but a range of other outcomes remains possible and even if we could be certain what percentage of the vote each party will get, we still wouldn't be much closer to knowing how this translates in terms of numbers of MPs.