These different responses to the Lib Dem surge are stiking, if predictable. Labour see Clegg as an opportunity: an opportunity to whitewash Brown's mechanical performance in the TV debate, and to keep the Tories out of government. Whereas the Tories now see them as a threat which needs countering, particularly after last night's YouGov poll. As various reports suggest this morning, you can now expect the Tories to angle their big guns onto Clegg and Cable.
Either way, it feels like a grenade has exploded and blasted shrapnel through the election campaign. And the Tories are still concussed, deafened, figuring out what to do next – when they should have protected against this weeks ago. Now they have only 19 days to refine their public response to the Lib Dems. Or they may end up having to do business with Clegg after the election.