The Lib Dem surge started before the leader debate

Political Betting this morning draws our attention to something that I was aware but seems to be getting lost in the media Lib Dem surge narrative and how the leader debate has been a "game changer". The surge actually started before the leader debate last Thursday.

Mike Smithson points out that there was a marginals poll that showed the Lib Dems were blunting Tory progress there and were up 5 points. That was a week before the debate.

He goes on:

Then exactly a week later a ICM finalised a standard national poll and found a sharp move to Clegg’s party putting the share up to 27 points. The survey had gone on over two days and almost all of if had been completed before the session started in Manchester.

Because that poll was published two days later it became part of the debate impact narrative.

So by the time that Nick Clegg made his opening statement the yellows were on a roll anyway. His assured performance was the icing on the cake.

Looking at the post debate polling as part of broad mood change amongst voters suggests that it might be more sustained than many are predicting.

I think this is important. It suggests that the surge might be more durable than some think and whilst I am sure the leader debate had an impact it may not be the whole story.