Heidi Allen has become the first Conservative MP to say publicly that she believes Theresa May will be gone in the next six months.
The South Cambridgeshire MP said she does not believe Ms May will remain Prime Minister "indefinitely" and said her premiership may now be a "period of transition" as the country negotiates Brexit.
She told LBC's Iain Dale: "If this was any other election in any other time in our history you could say yes the Prime Minister needs to stand down but this is different of course because we are about to start negotiating Brexit so that puts an entirely different complexion on that.
"We do need a Prime Minister at this moment."
Ms Allen, who is an outspoken backbench rebel, blamed the party's failure to win a majority squarely on the campaign.
She said she did not think it was wrong or arrogant to call a snap election and believes instead the party got its "product" wrong.
"Voters are our customers, we got our product wrong which tells me our sales team got it wrong", she explained.
She added: "I don’t think she was taking the electorate for granted or being arrogant by calling the election. I think she had a deeply held belief in what she had to do with Brexit and the dynamic of the House of Commons chamber would not allow her to do that easily.
"She thought it was right to get that stronger majority but the campaign was just very badly run."
Ms Allen, who regained her seat with a slightly decreased majority of just under 16,000, criticised a speech Ms May gave outside No 10 where she said she would be forming a minority government with support from Northern Ireland's DUP but did not apologise for the poor result.
She later apologised to the Tory MPs who lost their seats in a BBC interview shortly after Ms Allen was on air.
Ms Allen said: "It feels like she’s almost not aware of what has happened in the past 24 hours. Personally I am really struggling, I think we have lost some amazing, amazing MPs and there should be some acknowledgement, some responsibility.
"You can’t simply put your head down and say you have to get on with it".
She added that she wanted to see "an entirely new Conservative party".
"I want a Conservative party that sounds like the people of this country, that listens, that puts its hands up when it gets it wrong", she said. "It has been a terribly managed complain by too few people in the centre."
"I want a Conservative party that can look inwards and reinvent itself to be the party that it is and that I know it can be", she added.
The night saw several big scalps, including Ben Gummer who wrote the party's manifesto, as the party lost 12 seats with 649 out of 650 results declared.
Despite opinion polls putting the Labour party on track to loss swathes of seats, Jeremy Corbyn has come out of the election stronger with odds slashed on him becoming the next Prime Minister.
The party gained at least 29 seats, bringing their total up to 261, with the final seat – Kensington and Chelsea – yet to be called but believed to possibly be theirs.
Mr Corbyn said Labour had won a "huge mandate" to "carry forward a programme that challenges austerity, that challenges poverty and challenges inequality".
The result will be vindication for Mr Corbyn against his critics who said he could not win seats with a left-wing manifesto.
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