There will be lots of column inches wasted this morning trying to draw great conclusions from the Oldham East and Saddleworth by-election, when really by-elections don’t tell us a whole lot we couldn’t tell from the national polls anyway. The OES result was in the sort of ball park we should have expected from the ICM and Populus polls a week ago. They both suggested a Labour lead of 17 points, and in the event Labour won by around 10 points – but the publication of the polls showing the Liberal Democrats in a clear second probably encouraged further tactical voting and shifted support from the Conservatives to the Liberal Democrats in that final week.
An increase in Labour support of about 10 points is very much in line with the national picture anyway, more interesting is the degree of tactical voting by Conservative supporters in favour of the Lib Dems, which made up for a large loss of Lib Dem support to Labour and allowed them to retain their vote share. Populus’s poll already had 22% of 2010 Conservative voters switching to the Lib Dems, and presumably the actual figure was higher given the apparent shift in the vote since the pre-by-election polls.
If this became a common pattern at elections then it would have a significant effect, essentially reversing the pattern of tactical voting we’ve seen at the last four or five elections, especially if it also worked the other way with Liberal Democrat supporters being willing to back the Conservatives tactically. This is not as outlandish as it seems – remember the remaining rump support for the Liberal Democrats is made up of those more positively inclined towards the Tories, in a forced choice question of whether they’d prefer a Labour or Tory government, they opt for a Tory government by 51% to 16%. While it’s interesting to speculate, by-elections are strange creatures and it would be foolish to assume the level of tactical voting at a by-election would be replicated at a general election.
Following on from Oldham East and Saddleworth, later this year we should be getting by-elections in Barnsley Central and possibly Leicester South (if, as expected, Peter Soulsby becomes elected mayor of Leicester) and Belfast West (if, as expected, Gerry Adams steps down to contest Louth in the Irish general election).