The Tories took a projected voting lead in this month's council by-elections despite losing three seats.
Analysis of seven comparable results over the month suggests a 1.7% Conservative margin over Labour.
A calculation based on six wards fought both times by all three major parties gives a projected nationwide line-up of: C 39.8%, Lab 34.7%, Lib Dem 15.5%.
However the Tories may have benefited from the "two nations" trend identified in recent contests as they were defending six of the seven comparable seats - three of them unsuccessfully.
They held the only obvious C/Lab marginal in Brent, north London, but elsewhere went down to a shock Labour surge from fourth place at Gloucestershire county.
The Conservatives lost another seat to Labour in a Bassetlaw district, Nottinghamshire, ward which had already switched dramatically against them in last year's polls and were ousted by Lib Dems in a further defeat at Shropshire county.
No by-elections were reported this week. At least five are expected next Thursday.