Labour triumphed in the latest council by-elections, making two gains and easily defending a marginal seat.
The Liberal Democrats reversed a defeat by the Tories in May's main polls.
Labour's Victoria Quinn gained from the left-wing Respect group at Sparkbrook, Birmingham.
Party candidate Gary Poole had a landslide victory at St Mary's, Islington London Borough. The previous councillor had been elected as a Liberal Democrat but later became independent.
Also in the capital, Labour defended an Aldborough seat at Redbridge, where the other two ward councillors are Tories.
Lib Dem Cathy French won back a St Margaret's seat at Suffolk's Ipswich Borough which had been lost to the Conservatives in May.
The Green Party saw a small rise in its vote share in the two seats it contested both times, coming ahead of Tories at Birmingham and Islington.
Analysis of all four contests this week suggests a projected Labour nationwide lead of 7.7% over Conservatives. The calculated three party line-up is: Lab 40.5%, C 32.8%, Lib Dem 16.7%.
Birmingham City - Sparkbrook: Lab 3932, Respect 2301, Lib Dem 395, Green 179, C 133. (May 2011 - Lab 4382, Respect 3413, Lib Dem 569, C 243, Green 192). Lab gain from Respect. Swing 6.3% Respect to Lab.
Ipswich Borough - St Margaret's: Lib Dem 942, C 871, Lab 439. (May 2011 - C 1167, Lib Dem 1107, Lab 671, Green 211). Lib Dem gain from C. Swing 2.5% C to Lib Dem.
Islington London Borough - St Mary's: Lab 1128, Lib Dem 641, Green 317, C 282, BNP 22. (May 2010 - Three seats Lib Dem 1927, Lab 1894, 1869, Lib Dem 1839, Lab 1774, Lib Dem 1667, C 1210, 1170, 988, Green 716, 612, 445, Ind 192). Lab gain from Ind. Swing 9.6% Lib Dem to Lab.
Redbridge London Borough - Aldborough: Lab 1436, C 1071, Lib Dem 87, Ukip 83, Green 64, BNP 34. (May 2010 - Three seats C 2806, 2706, Lab 2663, 2602, C 2497, Lab 2432, Lib Dem 979, 840, 786). Lab hold. Swing 7.4% C to Lab.