The North Shropshire by-election on Thursday is shaping up to be the closest battle in the Tory stronghold in living memory, as weeks of scandal in Westminster show signs of angering the party faithful and eroding support for Boris Johnson.

The rural farming constituency bordering Wales is experiencing a rare moment in the national limelight, with much hanging on the outcome.

The Conservatives retain an unassailable 80-strong majority in parliament. But if the vote goes the wrong way for the prime minister it will intensify doubts over his leadership and embolden opponents inside and outside his party.

“We can’t change the government [on Thursday] but we can rock it,” said Grace Goodlad, landlady at the Bailey Head pub in Oswestry, the largest of five market towns across the constituency. “I want to make it clear that we are fed up,” she said.

North Shropshire has been one of the safest Conservative seats in the country since its creation in 1832. But that too could play into opposition hands in this by-election, which was triggered by the resignation of the Tory MP of 24 years, Owen Paterson, following the furore last month over parliamentary standards and lobbying. Many residents are resentful that the Conservatives have never needed to work hard for votes in the area.

“The sense of being taken for granted is very strong,” said Helen Morgan, former head of margin trading at British Gas, who is standing for the Liberal Democrats.

“There’s been no money from the towns fund here. Nothing on railways. From a political perspective, we are not on the map of places that need levelling up,” she said, referring to Johnson’s signature policy to address uneven development and consolidate Tory gains in the Midlands and North.

The Lib Dems are hoping to build on their shock by-election victory in Chesham and Amersham, another safe Tory seat they won in June, to add to the 12 seats they hold in parliament.

They have flooded far flung villages with activists, and Lib Dem leader Ed Davey has visited the constituency no less than five times during the campaign. The party, which increased its vote share in the area in May’s local council elections, should also benefit from tactical voters keen to give the Tories a kicking.

The opposition Labour party has a core of support in the area, but has never come close to winning. It has agreed at national level to take a back seat so that the Lib Dems can capitalise on Johnson’s recent woes, among them the evolving scandal over the party held in 10 Downing Street last Christmas when the rest of the country was locked down.

“What matters is the hypocrisy and the fact they are lying to cover up the cover up. When Boris says stay home, now we’ll all go out,” said William Henry, a retired bus driver.

But there is a mountain for opposition groups to climb. Paterson, who was found by a parliamentary standards committee to have received £500,000 to lobby government, bequeathed a majority of 23,000 to his successor candidate, Neil Shastri-Hurst.

A well-spoken lawyer from Birmingham, who served formerly in both the army and the NHS, he has sought distance from his predecessor and Westminster in a bid to win back trust.

Seemingly, all politicians have been tarred with the same brush, and an equal number of voters expressed disillusionment with the political system as a whole as they did anger at recent government scandals.

“I might not bother voting, I’m that fed up with it all,” said Kevin Battam, a family butcher in Oswestry, adding of Paterson: “He’s the one that’s been caught but probably they all do the same thing.”

Meanwhile, political loyalties in the area can run deep. Derek Tomley, a sheep farmer who, unlike the Brexit-supporting majority in Shropshire, thought Britain was better off in the EU, had plenty of gripes. He wasn’t budging though.

“Farmers are always better off under Labour,” he said before adding: “But I will vote Conservative because that’s the way I have been brought up.”

Nonetheless, the prime minister was sufficiently worried 10 days ago that he made a dash to the constituency to show his face. There is little doubt his stock has fallen, and the bonhomie and can-do message he brought to bear in the 2019 election is wearing thin.

“I thought he was going to be astute,” said Richard Lever, a brewer and avowed swing voter who plumped for Johnson in 2019.

“Instead he’s become a joke. I think a lot of MPs who were elected at the last election will lose their jobs because he’s been dishonest and undermined the good things that the Conservatives have done.”

More than half of a dozen traditional Tory voters questioned randomly on the main shopping street in Oswestry said, like Lever, that they would either vote against the party in protest this time or not at all.

The big uncertainty is the extent to which the vote will split. The Greens are putting up a popular candidate, Duncan Kerr, after winning control of the once “true blue” Oswestry town council in May.

Ben Wood, the 26-year-old Labour candidate, is fighting for every vote even if his party has decided not to deploy resources at scale. “We have knocked on more doors than we have for 20 years,” he said.

At the Bailey Head, Grace Goodlad said she would be voting tactically for the Lib Dems. “I am so fed up with corruption in the Tory party,” she said, taking cheer from the fact that bookmakers Paddy Power on Friday had the Lib Dems as odds-on favourites to win and had offered her £20 to shelve the bet she had made two weeks before.

“They don’t like the odds now so they have offered to buy me out.”

Source: Ft.com