The Liberal Democrats slumped in the first council by-election of the year.
The Tories easily held a Park ward seat at Windsor and Maidenhead Borough, Berkshire.
An 11% Labour surge saw the party miss second place by just seven votes compared with a margin of more than 500 in the 2007 main polls.
Windsor and Maidenhead Borough - Park: C 637, Lib Dem 156, Lab 149, Ind 47. (May 2007 - C 1098, 1046, Lib Dem 596, 575, Lab 72, 69). C hold. Swing 10.2% Lib Dem to C.