There's another one that has them only 3 points ahead too - you can't get anything from a single poll
Look at this chart of the polls though and you'll see what I mean about the lib dems
http://ukpollingreport.co.uk/voting-intention-2
2010 Tories ahead of Labour and LibDems high
As the Lib Dem support collapses to 2011 Labour overtake the conservatives and don't really recover.
If I were DC I'd be thinking about whether I could knife Cleggy and Get Vince Cable in
He's got the best chance of wooing back LibDem Voters who went to Labour
Trouble is if he's seen to be doing it it'll look like a push to the centre which will push Tories to UKIP
Delicate balancing act