Ex-British Army officer Johnny Mercer, who was only elected in 2015, said he would not have run in Plymouth Moor View “if the situation was like it is now”.
In an interview with The House magazine, he warned that if Tory internecine rows over Brexit let in Jeremy Corbyn “I don’t think we’d be forgiven for a generation and we wouldn’t deserve to be”.
The 37-year-old father of two said that with hindsight his pre-MP self “wouldn’t vote”, adding: “There’s no doubt about it that my set of values and ethos, I was comfortable that it was aligned with the Conservative Party.
“I’m not as comfortable that that’s the case any more.”
Mr Mercer is an Afghan veteran who served with 29 Commando, part of the Royal Artillery, before becoming an MP.
He took his Devon seat from Labour in 2015 and increased his majority to more than 5,000 last year, but warned the party was being led by “technocrats and managers” who were exposing it to “ridicule” over Brexit.
Since being elected he has joined the Defence Select Committee and campaigned for veterans, including those with mental health problems and others facing prosecution for alleged crimes during the Troubles.
He gained notoriety and column inches after being elected when it emerged he had appeared in a shower gel advertisement, in which he was shown soaping himself while half naked.
It is not the first time Mr Mercer has criticised the Conservatives from within.
In November he told the Telegraph the party “still seems punch-drunk” and was “in danger of losing credibility” after the snap general election in 2017 which saw the Tories lose their majority in Westminster.
The Remain supporter, who describes himself as being centre-right, told The House that Theresa May’s Chequers deal was “your classic professional politician’s answer” that pleases no one.
“People who pay our wages and vote for us expect us to make decisions and get on with government, not be fixated on us retaining our position,” he added, warning that the party had “lost this ability to fight, to scrap for what we believe in”.
He added: “The party will never really change until you have somebody who is leading the party who has won a seat and knows what it’s like to go out every weekend and advocate for what you just voted for that week.
“I sat down with a colleague the other day and I was stunned when [she] told me she had never been canvassing.
“A lot of these candidates, these safe seats come up and they just bounce around one to the other. It becomes something I don’t really recognise.”