The Conservatives will be looking to hold on to the heartland seat of Tiverton and Honiton when a by-election takes place today, on June 23.
It follows the high-profile departure of Neil Parish, the rural Devon constituency's previous Conservative MP.
Since the seat of Tiverton and Honiton was created in 1997, it has always been held by the Tories by a significant margin.
But today's vote takes place amid fears Sir Ed Davey's Liberal Democrats are parking their tanks on the lawn of Boris Johnson's party as they seek a third by-election scalp in the space of a year.
Why is there a by-election in Tiverton and Honiton?
A by-election takes place in a constituency when an MP's seat in the House of Commons becomes vacant between general elections.
This can take place when someone resigns, dies, is declared bankrupt, moves to the House of Lords, or is convicted of a serious criminal offence.
Neil Parish, who became a well-liked local MP after his election in 2010, resigned on April 30 after admitting he watched pornography twice in the House of Commons.
Mr Parish said he first visited the website accidentally after looking at tractors online, but then returned to it for a second time deliberately in a "moment of madness".
After telling The Telegraph's Chopper's Politics podcast last month he may run as an independent candidate, he has since decided against standing on June 23.
What happened last time?
At the 2019 General Election, in which Mr Johnson's party won a landslide victory, there was a swing of 3.3 per cent towards the Conservatives.
The Tories picked up 60.2 per cent of the vote (35,893 votes), followed by Labour on 19.5 per cent (11,654) and the Liberal Democrats on 14.8 per cent (8,807).
Voters in Tiverton and Honiton backed Brexit in June 2016, with 57.82 per cent voting to Leave compared to 42.18 per cent for Remain.
Who are the candidates?
Listed by surname (in alphabetical order), the candidates are as follows:
Jordan Donoghue-Morgan, Heritage
Andy Foan, Reform UK
Richard Foord, Liberal Democrats
Helen Hurford, Conservative
Liz Pole, Labour
Frankie Rufolo, For Britain
Ben Walker, Ukip
Gill Westcott, Green Party
The Liberal Democrats, who are aiming to secure victory in Tiverton and Honiton despite coming third in 2019, have chosen Richard Foord, a former Army Major who trained at Sandhurst, as their by-election candidate.
After drawing up an all-female shortlist, the Conservatives have nominated Helen Hurford, a former head teacher. Speaking to Radio Exe, she said she now backed Mr Johnson but declined to reveal how she would have voted in the June 6 confidence vote, had she been an MP.
Labour is fielding Liz Pole, who was also the party's candidate in 2019 when the Tories lost 7.6 per cent of their vote share compared to the 2017 poll amid a decline in the party's national fortunes.
Is there a Labour-Lib Dem 'electoral pact'?
There has been speculation about a 'pact' between Labour and the Liberal Democrats as the by-election will take place on the same day as another in Wakefield, which Labour believes it has a better chance of winning.
Labour has instructed its frontbenchers not to travel to Tiverton and Honiton to campaign in order to give the Liberal Democrats a better chance of victory, Politics Home reported last month.
A Labour spokesman insisted they would "fight for every vote" in the constituency, and both Sir Keir Starmer's party and the Liberal Democrats have categorically denied they have come to such an agreement.
Oliver Dowden, the Conservative Party chairman, accused the two parties of standing down for one another at May's local elections in order to boost the Left-wing and liberal vote nationwide.
How could a pact affect the outcome?
Working together against the Conservatives gives the Liberal Democrats and Labour a 20-point boost on polling day, a Telegraph analysis has found.
At the local elections last month, Labour gave the Liberal Democrats a clear run at 49 seats in the South West. The Liberal Democrats received an average vote share of 51 per cent in those seats, compared with a 29 per cent vote share in seats in the same area where Labour did run.
Similarly, in seats where the Liberal Democrats stood back, Labour received an average vote share of 46 per cent, compared with a vote share of 26 per cent where all major parties ran.
The Conservatives fielded at least one candidate in every ward.
What could the by-election result mean?
The result of the by-election will be announced in the early hours of June 24.
The Conservatives are fighting the election by defending their record of delivery for the local area, the Liberal Democrats have zoned in on farming and the Government's tax rises, and Labour has focused on the cost-of-living crisis.
If the Conservatives can hold on to Tiverton and Honiton, it will ease jitters about Mr Johnson's leadership among his MPs in heartland areas after he survived a confidence vote earlier this month, albeit with a bigger rebellion than was expected.
But if they suffer their first defeat in the constituency, there will be questions about whether Mr Johnson's brand is damaged beyond repair, as well as the direction of his Government's policies on taxation, the cost-of-living crisis and clean rivers.
Last year, the Liberal Democrats won two surprise by-election victories in traditionally safe Conservative seats as they triumphed in both North Shropshire and Chesham and Amersham.
If Sir Ed Davey's party can pull off a third such victory within a year, this will consolidate its role as the main challenger to the Conservatives in rural and heartland areas that have always been seen as 'true blue'.
But any result other than taking the seat from the Tories would disappoint the Liberal Democrats and suggest it was still struggling to connect with voters after a lacklustre 2019 general election showing.
Labour sources told The Telegraph the party does not expect to win the by-election, but will aim to win as many votes as possible to "send a message" to the PM