Liberal Democrats and Labour advanced against the Tories in the only council by-election in a week dominated by the hacking scandal.
Conservatives saw the majority slashed by nearly three quarters in their Norfolk County Council Old Catton stronghold as Lib Dems took second place.
There was a similar votes surge for Labour as Ukip slumped from runner-up last time to fourth.
However the previous contest in June 2009 was on the same day as European Parliament elections in which the arch Euro-sceptic party performed strongly.
The by-election result is a boost for Labour but also an immense relief for Liberal Democrats after hundreds of losses in May's main council polls. As recently as last week they lost a seat to the Tories at Purbeck, Dorset.
Old Catton is in the marginal Norwich North constituency taken by the Conservatives in a 2009 parliamentary by-election and narrowly won by them last year after boundary changes.
Norfolk County - Old Catton: C 664, Lib Dem 414, Lab 377, Ukip 107, Green 75. (June 2009 - C 1206, Ukip 402, Lib Dem 334, Lab 267, Green 262). C hold. Swing 10% C to Lib Dem.