With tactical voting likely to play a big part on Thursday YouGov has just published some new polling showing that overall a quarter of voters will now be putting their crosses against their first choice.
That seems a high figure and reflects the way the GE2019 narrative has revolved. For many Brexit is the overwhelming issue and many appear ready to switch to the party they dislike in order to have the maximum impact.
A lot, of course, depends on knowing in your seat which way you should vote to have the desired result. This of itself has caused a few sparks to fly with LAB preferring to make their point of reference GE2017 and the LDs more recent data.
What we do know from some of the Deltapoll single seat surveys is that more LAB voters are prepared to switch than LD ones to other way. That might, of course, change by Thursday.
The more effective tactical voting there is the more problematical the outcome could be for Johnson.