Boris Johnson will face a public showdown with MPs over whether he lied about Partygate within weeks.
The Privileges Committee, which is investigating his denials over lockdown-busting gatherings in No10, is set to begin hearings in March.
The Mirror understands it will grill witnesses on Tuesdays and Wednesdays for several weeks in the run up to Easter.
MPs will finalise a timetable for the hearings in the next fortnight or so.
The members of the committee have been wading through reams of written evidence that has already been submitted to its inquiry, including WhatsApp and emails between officials.
When the Mirror broke the story about gatherings in Downing Street during the height of the pandemic, Mr Johnson repeatedly insisted no parties had taken place and no rules had been broken.
No10 went on to become the most fined address in the country for Covid breaches after police issued 126 fixed penalty notices, including one to Mr Johnson and another to Rishi Sunak for a gathering to celebrate the ex-PM’s 56th birthday.
If Mr Johnson is found to have misled Parliament it could lead to him being suspended from the Commons.
A suspension of more than 10 days could lead to him facing a by-election in his Uxbridge and South Ruislip constituency.
Mr Johnson has promised to cooperate with the inquiry and has previously said he has "absolutely nothing, frankly, to hide".
The former PM and his aides have been ordered to hand a cache of evidence to the MPs.
The Privileges Committee has demanded diaries, photos, notes, and door logs relating to lockdown-busting events.
But there have been accusations of a cover-up following claims Partygate evidence was shredded.
A No10 whistleblower told ITV's Partygate podcast earlier this month: "There was a sense, and an implication, that we should start deleting evidence before an investigation. And a lot of people started shredding things."
The insider claimed phone pictures of parties were deleted and mock "awards" pinned on walls were destroyed.
According to the podcast, Mr Johnson allegedly joked that one Downing Street bash during the pandemic was "the most unsocially distanced" in the UK.
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