Populus shows Lib Dems down three points - UPDATED

The monthly Populus poll in the Times on Tuesday shows the Liberal Democrats down three points. Both Labour and the Conservatives are up marginally, meaning that the Labour lead remains steady at three points (though this is partially due to a slight change in Populus's past vote weighting - if they had used the same weighting as last month Labour would have been up 2 points).

Needless to say this is a contrast to the other pollsters, all of whom have either a Conservative lead or the parties level pegging in their most recent polls.

The survey was conducted between Friday and Sunday meaning that Kennedy's resignation happened halfway through the fieldwork and it's final effect may yet change - we won't see polls conducted after Kennedy's resignation for at least a few more days.

The survey also features Populus's first "party leader index" since David Cameron became Conservative leader. Cameron's average rating out of ten is 5.28, considerably higher than either IDS or Michael Howard, neither of whom ever breached the 5.00 mark. Despite this he trails behind Blair, who himself records his own best ever score of 5.33 on the index, beating his previous high of 5.31 recorded just after the 2004 Labour conference when he made the dual announcements of his heart operation and his intention to step down after a third term.

Given that there is no obvious reason for the boost in Blair's score, it may well be that both Cameron and Blair owe their unusually high scores to the fact that they weren't actively in the process of being removed by their party at the time and, therefore, must be doing comparatively well!

UPDATE: The change in weighting is only a tiny one - for the last few months Populus have been weighted recalled vote to the mid-point between the recalled vote in the survey and the actual 2005 result. Now there are a few months' data to work with they are weighting to the mid point between the actual 2005 result and the average of recalled vote in their last ten polls. While the change was to the disadvantage of Labour this month, overall the change won't make any partisan difference - it will just make the polls a bit less volatile. This does mean that ICM continue to weight their data in a way that is slightly more favourable to the Tories than Populus do.