Liberal Democrats won this week's only council by-election, comfortably defending a Winchester City Council seat.
But the result at Olivers Battery and Badger Farm saw a swing to Tories, with Labour more than doubling its vote share.
Analysis of eight by-elections this month gives a projected nationwide line-up of: Lab 39.4%, C 38.6%, Lib Dem 12.1%.
However six of the contests were in areas where Lib Dems are traditionally the main challengers to Tories. In most of these the Conservative vote held up.
This contrasted starkly with a huge swing to Labour in the only seat it was defending.
In the one remaining result, at Camborne in Cornwall, the party also managed a big recovery in a ward where it traditionally performed strongly but had fallen back in recent elections.
This confirms suggestions of a split between the two halves of Britain with the better-off possibly being concerned with the deficit and the poorer areas with cuts.
The key question, unanswered this month, is what is happening in the Con-Lab marginals. Evidence from December indicates Labour could also be performing well there.
If the Oldham East and Saddleworth parliamentary by-election is included in the calculations, the projected Labour lead rises to 3.3%.
Winchester City - Olivers Battery and Badger Farm: Lib Dem 894, C 604, Lab 162. (May 2010 - Lib Dem 1,615, C 943, Lab 162). Lib Dem hold. Swing 3.8% Lib Dem to C.