Populus give the Lib Dems a 5 point lead in Eastleigh

With under a week to go till the by-election tomorrow's Times has a Populus poll of Eastleigh (£). Voting intention now stands at CON 28%, LAB 11%, LDEM 33%, UKIP 21%.

If one assumes that the Ashcroft poll earlier this month was conducted by Populus using the same methodology, then this suggests that the Conservatives and Labour have both gone significantly backwards during the by-election campaign, while UKIP have advanced into a solid third place.

I'm hoping we may have more Eastleigh polling over the coming days so I'll update once it arrives or once we've seen the Populus tables.

UPDATE: Rick Nye has kindly sent me over the detailed tables for the Populus poll so here are a couple more things worth noting:

First, there is a very high level of don't knows or refusals. Populus interviewed 1001 people, but a quarter said don't know and a further 12% refused to give a voting intention. In a close race that high proportion of don't knows obviously have the potential to change things.

Secondly, Populus don't just ignore those don't knows. Like ICM they assume that a proportion of them will end up voting for the party they did in 2010. This adjustment made no difference to the Lib Dem lead, but reduced the reported level of UKIP support (as they didn't have many former 2010 voters to reallocate).

Without the reallocation of don't knows the topline figures would have been CON 26%, LAB 12%, LD 31%, UKIP 25%. The reallocation of don't knows has worked very well for ICM and Populus at general elections, improving their accuracy, but I remain uncertain about how well it works at by-elections. Without it the position between UKIP and the Conservatives is very tight.

Thirdly, everyone assumes that the UKIP support comes mainly from the Conservatives. It isn't quite the case. 17% of 2010 Tory voters are saying they would vote UKIP, but so are 11% of 2010 Lib Dem voters and 10% of 2010 Lab voters.