Rishi Sunak faces a major electoral test next month as voters head to the polls in the ex-Tory MP Nadine Dorries's former seat.
The ballot in Mid-Bedfordshire will take place on October 19 and just two weeks after the Prime Minister delivers a major speech to his divided party.
It comes after Ms Dorries - a close ally of former PM Boris Johnson - finally resigned from the Commons almost 12 weeks after a pledging to go with "immediate effect". In a bitter swipe she suggested the Tories, who continue to trail Labour in the national polls by around 20 points, cannot win an election under Mr Sunak.
In an attempt to manage expectations, the Tory Cabinet Minister Mark Harper claimed last week the Tories face a "tough" battle to keep the seat - despite a 24,000 majority.
Labour came second in the constituency at the 2019 general election and the party is hopeful of snatching the seat held generally by the Conservatives since 1931. In July Keir Starmer's party secured a historic victory in Selby and Ainsty overturning a massive 20,000 Tory majority in a hammer blow to the Prime Minister.
But the Liberal Democrats also believe they have a chance in Ms Dorries's former constituency to continue their run of delivering by-election shocks to the Tories.
Mr Starmer will also face a key test in a crucial by-election being held in Scotland on the eve of the Labour Party's annual conference. The vote was called after the former SNP MP Margaret Ferrier lost her seat in the Commons last month as thousands of her constituents signed a recall petition.
She held a majority of 5,230 in Rutherglen and Hamilton West - a seat Labour is seeking to win to show signs of the party's revival north of the border.
The constituency's by-election has been confirmed for October 5 and will be a key battleground between the SNP and Labour. Speaking on Tuesday, Labour's leader in Scotland, Anas Sarwar, said: "This is a significant by-election. There's no escaping that, but we are not complacent."
Speaking on how a win would impact the party ahead of next year's general election, he said: "We've got to continue that momentum, but that momentum is there for a purpose. "For far too long now the people of Scotland and the UK have been let down by two failing governments."
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