The question many people are asking right now following a litany of scandals marring both the government and the prime minister is: is time running out for Boris Johnson as prime minister?
Why are people asking this now?
The anger and discontent on the PM's own backbenches reached a new high this week, culminating in 100 MPs voting against the government's latest COVID measures in the largest rebellion Johnson has suffered since he became PM.
But it's not just anger at policy around COVID restrictions. There is also significant frustration with the personal leadership of Johnson. This intensified recently with the handling of the Downing Street Christmas Party scandals, which itself followed hot on the heels of the Owen Paterson lobby scandal; the second jobs scandal; the flat refurbishment scandal; and the HS2 U-turn. There was also a particularly bizarre 'Peppa Pig' speech.
And on Wednesday, senior Conservative MP Sir Geoffrey Clifton-Brown said the prime minister's premiership is in "some danger", saying "the prime minister has really got to think very carefully about how he's going to reset his performance. If he doesn't realise that, then he will be in much bigger danger."
The last thing the PM needs would be a by-election defeat in an ultra-safe Tory seat, which is exactly what he faces in North Shropshire today.
If that triggered even more anger, this is how the Tories could defenestrate their own leader...
How would it begin?
There are various ways a sitting prime minister can be removed: their own party's mechanisms; MPs passing a vote of no confidence in parliament; and losing an election.
It is unlikely MPs will call for a no confidence vote, and there isn't an election on the cards - so it's Johnson's own party that poses the biggest threat to him.
The Conservatives' backbencher 1922 Committee would lie at the heart of any attempt by MPs to remove him, and it often meets to hold Tory leaders and senior MPs to account if there is unhappiness within party ranks.
It can also convene if the prime minister, or a secretary of state, is concerned that MPs may rebel on crucial votes in the House of Commons - which is what the prime minister did on Tuesday night to attempt to convince rebels to vote with the government.
Sending the letters
The process to remove Johnson would start by the submission of letters of no confidence to the committee's chair, Sir Graham Brady.
Tory MPs would have to submit 54 letters to the 1922 Committee chair expressing dissatisfaction in Johnson's leadership to trigger a vote of no confidence, 15% of all sitting Tory MPs - and Johnson would need more than 50% of a no-confidence vote to survive.
The decision to send in letters about a sitting Conservative prime minister is a hugely significant move - but there were already reports of letters being sent in before the hugely damaging Downing Street Christmas Party scandal which has seen Labour storm ahead in the polls.
And there are growing reports more MPs are considering submitting letters in the aftermath of the huge rebellion in parliament on Tuesday.
According to the Telegraph, MPs have also been told they can even email letters over Christmas.
Should Johnson lose the vote of no confidence, then a Conservative party leadership contest would ensue - with MPs throwing their names into the hat to be future prime minister.
Hopefuls would need two nominations from other Tory MPs to run, after which party MPs would hold a ballot to choose the candidates; those with the lowest votes are eliminated until only two remain.
As it's entirely an internal party matter, a general election is not needed - and the decision of who becomes the leader, and in this case future prime minister, is down to the party with Conservative members having the final say on the final two candidates.
It is by this process that Boris Johnson became prime minister in July 2019 following the resignation of Theresa May.
The entire process usually lasts around 12 weeks, with MPs vying for leadership launching campaigns in a similar way to a general election.
And there are already reports that senior Conservative MPs, like chancellor Rishi Sunak and foreign secretary Liz Truss - who are immensely popular in the party - have their eyes on the top job.
When did this last happen to a sitting prime minister?
Johnson's predecessor, Theresa May, had a narrow escape from the 1922 Committee in 2018 after 15% of her MPs submitted letters of no confidence to 1922 Committee Chair.
Dissatisfied with the prime minister's management of Brexit, she was forced to face the brutal process which strikes fear into the heart of any Conservative prime minister.
The letters triggered a vote of no confidence, which May survived - but only on the basis that she would step down once Brexit was delivered, and not lead the party into the next election.
Read more: Boris Johnson urged to use Christmas to consider if he has the authority to lead