Rishi Sunak will on Thursday face two crucial by-election tests when the polls open in Mid Bedfordshire and Tamworth.
The Conservatives are battling to hold onto the constituencies, previously been regarded as Tory “safe seats", following a number of defeats at the polls.
Former Culture Secretary Nadine Dorries commanded almost 60 per cent of the vote share in Mid Beds at the 2019 General Election. The constituency has been held by the Tories for nearly a century.
Chris Pincher won Tamworth with 30,542 votes compared to Labour's 10,908.
But public feeling has soured after both sitting MPs left their positions under a cloud of scandal and the Government attempts to get a grip on sky high living costs.
Ex Tory whip Mr Pincher quit as Tamworth MP after losing his appeal against a suspension for drunkenly groping two men.
Devout Boris Johnson ally Ms Dorries took more than 10 weeks to officially resign after first announcing she would step down in June when she was refused a peerage.
A leaked internal Tory party memo, seen by Sky News, outlined concerns that there was “enormous discontent” with the ex cabinet minister on the doorstep over her delay to quit the Commons.
It’s a sentiment echoed by Tory MPs.
One told the Standard: "It’s not exactly an easy thing to explain to voters on the doorstep. It's gone down like cold sick."
Labour, fresh from a “seismic” by-election win in Rutherglen and Hamilton West last week, is hoping the discontent will help the party flip the huge Tory majorities.
The party's candidates are now favourite to win both seats, according to bookmakers,
However Labour hopeful Alistair Strathern, who was until recently a councillor in Waltham Forest, faces fierce competition from the Lib Dem Emma Holland-Lindsay in Mid Beds.
Leader Ed Davey has visited the constituency half a dozen times and hundreds of the party's activists have flooded the area.
Elections expert Lord Robert Hayward told a Tory party conference event earlier this month that the Lib Dems and Labour were “tearing lumps out of each other” in a bid to win the seat.
The battle between the two parties has given the Tories hope the vote could be split and allow their candidate, Festus Akinbusoye, to come through the middle.
Tamworth is set to be a straight fight between the Tories and Labour.
Conservative candidate Andrew Cooper was this week condemned for appearing to have suggested out-of-work parents who cannot feed their children should "f*** off" in an old social media post.
The councillor in 2020 posted a photo on Facebook of a flowchart asking the question: "Can you feed your kids?"
The diagram suggests that out of work parents who pay for "TV Sky/BT/ETC", or "have a phone contract + £30" should "f*** off" rather than seek help.
A screenshot of the post was shared on the local Facebook page, Spotted Tamworth, just days before the polls opened alongside an anonymous message reading: "Lovely potential MP!! Wants to starve the children!! He won't get my vote! Absolute cretin!"
Nearly 20 per cent of children live in relative poverty in the constituency, according to the latest constituency data.
Mr Cooper said: "I think most people in Tamworth would agree that benefits are not there to pay for luxuries. There are too many people on out-of-work benefits and there needs to be improved incentives to get people into work.
"Both the Prime Minister and Chancellor have spoken about the need to get people off welfare and into jobs. That's why I want to be the local MP in Tamworth - so I can support local families and help get more people into work."
Rishi Sunak did not condemn the alleged comments when challenged at Prime Minister's Questions on Wednesday.
Labour MP Stephanie Peacock, who is leading the party's by-election campaign in Tamworth, said: "The Tories have overseen 13 years of next to no growth, before crashing the economy. The result is a third of children in Tamworth are growing up in poverty and two thirds of them are in working families.
"It shows a complete lack of understanding of the challenges facing families in Tamworth that the Conservative candidate is telling parents who are struggling to make ends meet to 'f*** off'."
Mid Bedfordshire by-election: Who are the candidates standing?
Festus Akinbusoye - Conservative
Sid Cordle - Christian Peoples Alliance
Dave Holland - Reform UK
Emma Holland-Lindsay - Liberal Democrats
Ann Kelly - Monster Raving Loony Party
Prince Ankit Love, Emperor of India - independent
Gareth Mackey - independent
Chris Rooney - Mainstream
Cade Sibley - Green Party
Alistair Strathern - Labour
Alberto Thomas - Heritage Party
Alan Victor - True and Fair Party
Antonio Vitiello - English Democrats
Tamworth by-election 2023: Who are the candidates standing?
Robert Bilcliff, UKIP
Andrew Cooper, Conservative
Ian Cooper, Reform UK
Sarah Edwards, Labour
Howling Laud Hope, The Official Monster Raving Loony Party
Dr Sue Howarth, Green Party
Peter Longman, Independent
Sunny Virk, Liberal Democrat