Boris Johnson is facing further calls to resign, as Tobias Ellwood became the latest Tory MP to say he wants to oust him from office.
The Bournemouth East MP said he would be submitting a letter of no confidence in the PM, amid the ongoing row over lockdown parties in No 10.
He joins colleague Peter Aldous, who said on Tuesday he would be doing the same.
At least 54 Tories must submit letters to set up a vote on the PM’s future.
A handful of Tory MPs, including Scottish Tory leader Douglas Ross, have said they have submitted letters to the backbench 1922 Committee, which runs leadership contests.
But the exact number of letters submitted is not known.
Mr Ellwood, who chairs the Commons Defence Committee, said it was “time to resolve this” as the Conservative Party is “slipping into a very ugly place”.
Speaking to Sky News, he added it had become “just horrible” for the party’s MPs to “continuously have to defend this to the British public”.