For once I do not need to add a caveat about changes being inside the margin of error and not necessarily being significant – today’s YouGov poll for the Sun shows a huge surge for the Liberal Democrats on the back of Nick Clegg’s debate performance, putting the Lib Dems ahead of Labour and into second place. The topline figures are CON 33%(-4), LAB 28%(-3), LDEM 30%(+8). The surge in Lib Dem support therefore seems to have come pretty evenly at the expence of the Conservatives and Labour. This is the highest level of support YouGov have recorded for the Liberal Democrats since the aftermath of the Brent East by-election victory, way back in 2003.

On a uniform swing these figures would leave Labour the largest party, despite being in third place. The Lib Dems would have around about 100 seats. In reality though, it’s almost impossible to say how this would translate into an election result. In 1983 when the SDP Liberal Alliance almost pushed Labour into third place UNS was actually a pretty good predictor of the result, but who knows how it would work in practice now. If the Lib Dems stay at this sort of figure I’m sure we’ll eventually see some more detailled polling to see how the electoral plates are shifting, but till then it is speculation.

The questions now are firstly whether other polls show the same thing? Secondly how long this boost lasts. Is it mostly a publicity boost that will rapidly disappear, or will it stick around? Boosts after things like the Brent East by-election didn’t last long, but in this case the Lib Dems will probably enjoy a further publicity boost from the very fact there are polls showing them in second place, and on top of that there are two more debates to go. Thirdly, how does this change the narrative – can the Lib Dems start painting themselves as a contender to actually win?