Carlisle's Conservative MP John Stevenson has said that "the prime minister should submit himself to a vote of confidence" once investigations into partygate have concluded.
Boris Johnson was issued a fixed penalty notice after being found to have broken lockdown rules.
A debate is underway on whether he misled MPs after initially denying that he broke the rules.
Investigations are still ongoing with the Metropolitan police as well as the full Sue Gray report still yet to be issued.
John Stevenson said: "I think you've got to follow due process, there are still ongoing police investigations."
However, once these have concluded he thinks the PM needs to "draw a line under this".
He said: "My own conclusion though is at the end of this the prime minister should submit himself to a vote of confidence by the Conservative parliamentary MPs because I think we have to draw a line under this once and for all.
"Is Boris Johnson going to be the leader of the Conservative party at the next general election or not?"
However, he says he does not yet know how he would vote if this were to happen.