The Conservatives lost a seat to the Lib Dems and were pushed into fourth place by the far-right National Front after a council by-election in Hull.
Lib Dem councillor Andy Sloan defected to the Conservatives, but later quit the authority due to work commitments.
Lib Dem Linda Chambers polled 1,306 votes to win the Drypool seat. Labour's Gary Wareing was second with 891 votes.
Conservative Andrew Allison polled 117 votes, in last place behind the National Front's Mike Cooper with 184.