Boris Johnson has deflected questions about his leadership, saying he would still be prime minister in October.
Mr Johnson is facing a Commons investigation into whether he misled MPs by telling them Covid laws in No 10 were followed, as the row over lockdown parties continues.
But a senior Tory MP has said it is “a matter of when not if” the PM faces a no confidence vote from his own MPs.
Earlier, minister Conor Burns insisted the PM would not be stepping down.
He said the PM had “unfinished business” in No 10, and was determined to “rebuild trust” with the public.
Mr Johnson was speaking during a trip to India, where he deflected questions on his future, saying that people wanted the government to “get on and focus on the issues on which we were elected”.
Last week, Mr Johnson, his wife Carrie and the Chancellor Rishi Sunak were fined by the police for breaching lockdown rules by attending a gathering to celebrate his birthday.
Speaking to the BBC’s Today programme, chair of the Defence Committee Tobias Ellwood said Conservative MPs were “deeply troubled” and warned that the ongoing row about lockdown parties was doing “long-term damage to the party’s brand”.
He accused No 10 of lacking “discipline, focus and leadership” and predicted the prime minister would face a vote of no confidence, which could force him out of office.
Mr Johnson had previously told MPs laws were not broken in Downing Street, leading to accusations from opposition parties that the prime minister had misled them.
After more than five hours of debate yeserday (April 21) evening, MPs were asked if they supported launching an investigation into Mr Johnson.
No one opposed the proposal, so the motion was approved without a formal vote.
Speaking after the vote, he added: “Boris Johnson has lost the trust of the public over parties held in Downing Street during lockdown.
“Now it’s clear he has lost the confidence of his MPs.”