Last week, the Liberal Democrats increased their parliamentary representation to 13 by winning the Brecon and Radnorshire by-election.
The most important thing is that the result wasn’t a surprise. I say that for several reasons. The obvious one is that had the Liberal Democrats failed to win it, the feel-good factor around the party would have dissipated and Jo Swinson’s leadership could have been wrecked almost on day one.
But the more important one is that the Brecon and Radnorshire result is essentially exactly what we’d expect given the polls. That’s important because when the polls have been off, by-elections have tended to provide hints that they weren’t functioning properly. In the 2010-5 parliament, Labour consistently did worse than we’d have expected them to do from the polls at the time.
The problem is, with four parties bunched fairly close together, that all of the polls that are “about right” could mean wildly different things, and also that the polls are right now doesn’t mean they will necessarily play out that way in a general election.
We don’t know to what extent there will be tactical voting in England, Scotland and Wales and if there is, we don’t know on what lines they will be. If there is a great deal of tactical voting on constitutional lines in Scotland that is good news for the Conservatives and would mean they do better than the polls suggest. If there is a great deal of tactical voting on Remain-Leave lines in England then that will be bad news for the Conservatives.
But for now, the significant lesson of Brecon and Radnorshire is that the polls seem to be doing about right.