Activity in Westminster is largely on pause as MPs wait for Sue Gray to deliver her report on lockdown breaking parties in No.10.
Boris Johnson has pleaded with his backbenchers, many of who want rid of him, to wait for the results of the civil servant’s inquiry before judging him.
At the time of publication, the expectation was it would not be delivered until Monday. Johnson’s immediate future could be decided very quickly once it drops.
Will the prime minister resign?
Johnson has repeatedly refused demands, from some Tory MPs as well as Labour leader Keir Starmer, that he resign immediately.
But speaking during PMQs on Wednesday he did appear to concede if he was shown to have misled parliament he would have to walk.
In December, Johnson told parliament that Covid rules were “followed completely in No.10”. The PM said he had been “repeatedly assured” there were no parties.
If Gray's report provides evidence he knowingly lied to MPs, that could be fatal for his premiership.
On top of this, the Metropolitan Police have also launched an investigation into rule-breaking gatherings in Downing Street and Whitehall.
If Johnson is interviewed under caution by police, he is likely to face further calls to quit.
In 2007, Downing Street believed Tony Blair would have to resign as PM if he had been interviewed under caution during the cash-for-honours scandal. This was avoided as he was quizzed as a witness.
But the police inquiry is likely to take some time, and events in parliament are likely to move faster. Many MPs are said to be set to submit letters as soon as Gray's report comes out.
If Johnson does go, it will most likely be because his own MPs kick him out.
How a leadership challenge works
To mount a leadership challenge, 15% of Conservative MPs have to submit a letter.
Based on the current size of the party in the Commons, this means 54 Tory MPs have to get out their pens.
The letters are secretly sent to Sir Graham Brady. The veteran Tory MP leads the body of all backbench Conservative MPs known as the 1922 committee.
Only Brady knows how many letters he has received. In 2018, when MPs mobilised to oust Theresa May, Brady said he did not even tell his wife how many he had locked in his safe.
The rebels and Johnson’s allies are currently engaged in a furious briefing battle, with No.10 trying to persuade backbenchers to stick with the PM and even withdraw their letter if one has been sent.
But if and when 54 letters are delivered, a no confidence vote in Johnson would be held.
Depending what time the threshold is reached, this could even happen on the same day.
All 359 Tory MPs would vote in a secret ballot, if more than 50% vote against Johnson he would be removed as leader.
But if the rebels fail to reach that threshold Johnson would get to keep his job.
What happens if he survives the vote?
If Johnson survives the no confidence vote, party rules mean another no confidence vote could not be held for another year.
This happened in December 2018 when Tory MPs botched an attempt to get rid of May. She ultimately managed to cling on to the leadership until June 2019.
Johnson’s authority would be hugely damaged even if he did win the vote.
But it would inoculate him against another formal challenge immediately after the local elections in May, which based on current polls could be painful for the Conservatives.
What happens if he loses the vote?
If Johnson loses the no confidence vote then a leadership contest is triggered. He is not allowed to stand for re-election as leader but would likely stay in post until his successor is chosen.
How does the leadership election work
Conservative Party leadership elections have two parts.
The first stage sees Tory MPs vote in a series of rounds, whittling the list of candidates down to a final two. In the 2019 leadership race this took roughly two weeks.
The second stage sees the final two candidates go to a vote of Tory members.
In 2019, when Boris Johnson took on Jeremy Hunt, this took around a month.
Tory leadership candidates
Rishi Sunak, the chancellor, is seen as the frontrunner in any contest, followed closely by foreign secretary Liz Truss.
Jeremy Hunt, the former health secretary who stood in 2019 and has spent his time since chairing the Commons health committee, has not ruled out standing again.
Michael Gove, the levelling up secretary who famously torpedoed Johnson’s 2017 bid for the leadership, could try a third time for the top job.
Penny Mordaunt, the trade minister and former defence secretary, has been touted as a unity candidate able to bring together pro-Brexit and socially liberal wings of the party.
Other outside bets include foreign affairs committee chairman Tom Tugendhat and former Brexit minister Steve Baker. And Matt Hancock might be down but never appears to consider himself out.