Suddenly, after remaining static for months, the polls are moving again. The latest Reuters/Ipsos-MORI survey, carried out after the EU summit, puts the Tories in the lead for the first time this year, with support for Cameron's party rising seven points to 41 per cent and support for Labour falling two points to 39 per cent. Similarly, the latest daily YouGov poll has the Tories two points ahead of Labour, the first time they've led with that pollster since December 2010. Labour's lead, which has stood at five to six points for the last month, has evaporated.
Of course, correlation does not equal causation, but it certainly seems as if Cameron's EU stance has benefited his party. This may seem surprising, since, as polling by Ipsos-MORI regularly shows, only four per cent of voters regard Europe as one of the most "important issues" facing the country. And yet it can still shift polls. There are at least two plausible reasons why. Firstly, for a minority of voters, Europe clearly is very important. The rise in support for the Tories has coincided with a revealing fall in support for Ukip. For a period, with ratings as high as seven per cent, Nigel Farage's party was snapping at the Lib Dems' heels but the latest YouGov poll has them on just three per cent. Britain's eurosceptics are returning to the Conservative fold.
Secondly, as UK Polling Report's Anthony Wells points out, Cameron's bulldoggery (and the favourable headlines it garnered) may have changed perceptions of the PM himself and his leadership. He notes: "[I]f it makes people think David Cameron is a stronger leader who stands up for the country it may improve perceptions of him across the board." Cameron's personal approval ratings remain higher than Miliband's, a fact Tory strategists have continually drawn comfort from. As I've noted before, leadership ratings are often a better long-term indicator of the next election result than voting intentions. Labour party frequently led the Tories under Neil Kinnock, for instance, but Kinnock was never rated above John Major as a potential prime minister.
It remains to be seen whether the Tory surge hardens into a permanent advantage. But the fragility of Labour's lead has been exposed for all to see. Miliband's party will still likely walk to victory in tomorrow's Feltham by-election but an unusually strong Conservative showing would raise further questions for Labour.