By-election: Tories cheered by poll data despite council seat loss
Candidate Gordon Cowan took a seat in Kent's Dover Town division with a big swing.
The outcome is a disappointment to Conservatives as it comes in Dover constituency where they achieved a spectacular general election gain in May.
However Labour faced dismay in east London's Tower Hamlets Borough where there was a win for Fozol Miah of the left-wing Respect party.
The result was technically a Respect gain from independent after the resignation of former Labour council leader Lutfur Rahman after his election as mayor of Tower Hamlets left a vacancy.
He had defied the party's decision to bar him from running as its mayoral candidate by standing as an independent backed by Respect.
He won by a landslide.
Despite losing the Kent seat, the Tories were set to be cheered after analysis of six comparable results this week suggests a projected 4.6 per cent nationwide lead for them over Labour.
There are still two more by-elections before Christmas: in Wiltshire on Tuesday and East Hertfordshire on Thursday.