In a stunning turn of fortunes, the Conservatives slipped into third place in the Gaywood South by-election, with the Liberal Democrats coming out on top.
Rob Colwell will now represent Gaywood South at Norfolk County Council, following an almost 30pc swing towards the Lib-dems.
Thomas Smith, who previously represented Gaywood South, stood down last month after being offered a job in London.
The Conservative member had only been re-elected on May 7.
Speaking after the results were announced, Rob Colwell said: “I am just so grateful to the people of Gaywood South who put their faith in me to represent them.
"I have learned a lot about the issues that matter to my neighbours and local communities, and am so proud now to have the chance to represent them in County Hall."
Mr Colwell said it was an "amazing swing" toward the Lib-dems, which he put down to a variety of factors, including the conservative-led West Norfolk Council's support of the Parkway development, but especially the Queen Elizabeth Hospital "going to ruin".
"People out on the campaign trail have been so supportive," he said.
"It makes all the difference having someone local who is known in the area, who wants to be a strong voice for Gaywood South."
Speaking about his aims for his time in county hall, Mr Colwell said he wants to be a "polite nuisance".
Adding: "I want to really concentrate and make some noise about the road system [in King's Lynn], one problem and the whole system grinds to a halt and people feel stuck in their homes when the holidaymakers arrive."
Deputy group leader and member for Cromer Tim Adams said the results showed the Tories were losing popularity as people returned to the issues that matter locally as they emerge from the pandemic.
Adding: “Labour and the Tories threw the kitchen sink at this election but it just goes to show they can’t take people for granted.”
Results for Gaywood South Norfolk County Council by-election were: Colwell Rob (LD) 648, Bartrum Micaela (L) 561, TRASK Phil (C) 378, Stone Michael (UKIP) 28, Talbot Robin Lee (I) 35.
The Lid Dems have not won a seat in West Norfolk since 2005.
The turnout of the election was 17.32pc.
LDEM: 39.3% (+28.0) LAB: 34.0% (-1.6) CON: 22.9% (-25.3) IND: 2.1% (+2.1) UKIP: 1.7% (-3.2)
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