Tom Tugendhat has criticised the "sniping and infighting" during his party's process of selecting its new leader.
The backbencher's remarks came the day after a leadership debate on ITV which saw the candidates descend into outright hostility on issues including the economy, transgender rights, and trust in politics.
Tugendhat, the MP for Tonbridge and Walling, was eliminated from the Tory leadership contest on Monday night.
The debate followed days of increasingly bitter briefing wars in the press.
Tugendhat said he has "deplored" some of the behaviour.
“Let’s not forget that when this is over we must come together," he said.
"We must unite and we must speak as one.
"I have deplored the infighting, the sniping, the blue on blue, the attacks and the smears. We do not need this, now or ever. Because we are fighting on every flank.
“The Labour Party, resurgent but easily beatable, are benefitting from our disunity and division.”
The second of the televised debates was on Sunday night - with former chancellor Rishi Sunak accusing foreign secretary Liz Truss of peddling “something-for-nothing” economics.
In turn, Truss accused Sunak of choking off economic growth with tax hikes, which are currently at their highest level in 70 years.
In the aftermath, Sky News announced the leaders' debate for Tuesday night had been cancelled after Truss and Sunak pulled out - with reports the move was due to fears in the Tory party that the debates were creating a toxic impression.
The exit of Mr Tugendhat from the contest was not unexpected, with the Tonbridge and Malling MP trailing behind rivals in the bid for Tory MP backers.
He had addressed his likely fate head-on earlier, dismissing any suggestion that he would drop out.
It is understood that at the behind-closed-doors hustings organised by the backbench 1922 Committee, he told MPs that it had been suggested to him that he should step aside and back another candidate.
He said: “It will come as no surprise that some have suggested I could leave with a job as well. But my view is clear. It is not for me to make that decision – it is for you.”
Tweeting after the contest, he said: “Although it wasn’t to be today, I am immensely proud of the positive vision we put forward for our country.
“Thank you to all those who supported me and believed in #ACleanStart.
“This is only the beginning!”,
The final two candidates of the original 12 will be decided by the end of this week, with the victor announced on 5 September after Tory members have their say.
On Monday, Labour leader Keir Starmer said Tory party was "tearing each other apart".
“I can see based on what I’ve seen in the debates so far why they want to do so because this is a party that is out of ideas, out of purpose, they’re tearing each other apart," said Starmer.
“And I think for millions of people, particularly with the heatwave today, they’ll be saying I want a government that’s focused on the day job, that’s getting on with resilience for today and tomorrow, however long this heatwave goes on, and focused on the cost-of-living crisis.”
Watch: Tom Tugendhat: Boris Johnson's partygate account more fictional than reality