Scroll down to explore the data in depth
There are now eight months to go to the general election. Although none of us can be sure what will happen next May, what we can do is explore the main factors likely to determine the outcome. There are several key factors that will determine the result, and these are set out in the charts below.
I start with four scenarios: The first of these assumes that people will vote in line with the average of recent YouGov polls: Labour 37 per cent, Conservative 34, Ukip 12, Liberal Democrat 8. Compared with 2010, this means that Labour would be up seven points, the Tories down three, Ukip up nine, Lib Dems down 16. I have applied these changes to every constituency (actually, all bar one: I assume the Green MP, Caroline Lucas, will successfully defend her 1,252 majority over Labour.) The result is that Labour would end up with 340 seats, an overall majority of 30.
In the past, Conservative governments have recovered ground in the months leading up to elections. I show three alternative “recovery” scenarios: 36 per cent each for Labour and Conservative, a 37-34 per cent Tory lead and a 39-33 per cent lead. I have left Ukip and Lib Dem support unchanged.
Equal votes would leave Labour just three seats short of an overall majority, and 38 ahead of the Tories. A three-point Conservative lead would leave the two main parties virtually level-pegging in seats. A six point Tory lead would give the party 327 MPs and an overall majority of four.
However, I would be surprised if uniform swing (the calculation widely used to translate opinion polls into seat numbers) will work as well next year as in the past; and I doubt whether Ukip and the Lib Dems will end up on their present levels. In the table I set out how six different factors might affect any uniform swing calculation.