Johnson's Conservative Party is facing a fight to retain the parliamentary seat for North Shropshire in a so-called by-election, triggered by last month's resignation of Owen Paterson after he was found to have broken rules on paid lobbying.

If the Conservatives lose what has long been a loyal seat, it would be yet another blow to Johnson, who is under pressure after experiencing the biggest parliamentary rebellion against his government and over scandals such as reported parties in his office last Christmas when Britain was in a COVID-19 lockdown.

The battle pitches the Conservatives against the Liberal Democrats, with several lawmakers saying they believed the governing party would lose the seat in the mostly rural constituency, a further erosion of support in traditionally Conservative-supporting regions.

Conservative candidate Neil Shastri-Hurst, an army medic and barrister, said he was campaigning mainly on local issues, admitting that voters were concerned by scandals, such as Johnson's former press secretary, Allegra Stratton, captured on video joking about a lockdown-breaking party in Downing Street.

"I’d be being disingenuous if I didn't say the video hadn't been raised on the doorstep, and clearly it was egregious," he told Reuters, adding it was right that Johnson ordered an inquiry into the reported parties at his residence.

"I’m in the army so I know not to be complacent: from day one we've been fighting hard in this campaign," he said.

Ben Wood, a local councillor running as the opposition Labour Party candidate, said he was doubtful that the Liberal Democrats could wrest control from the Conservatives.

"People are angry, they feel like they've been taken for granted," he said.

"I’m absolutely fighting to win this one," he said. "I'm running a local campaign on public services, but it's also offering that alternative in decency, honesty, integrity, which people aren't getting from the Tories."

Several voters interviewed in Whitchurch, a sleepy town of around 10,000 people in the district, were more interested in local issues than those dominating the national stage.

Silvia, 74 and a life-long Tory voter, voted Liberal Democrat for the first time.

"It's very much a protest vote," she said. "I’m not happy with the way that local issues are being dealt with and we seem to be sidelined."

Caroline Monschke, a 64-year-old supermarket worker, said she would reluctantly stick with the Conservatives.

"It's like voting from bad to even worse: no matter what they say they all end up doing the same thing: making working people's lives a misery and lining their own pockets," she said.

"I don't care about Christmas parties, but they shouldn't be doing one thing and telling us another."