Northern Ireland Secretary of State Brandon Lewis arrived at Number 10 Downing Street on Wednesday evening as he was pictured walking through the famous door.
Mr Lewis was met with a barrage of calls from the media as he stepped out of his car but said nothing to reporters as he quickly walked through the door.
Earlier in the evening there had been a brief flash of excitement as rumours swirled Mr Lewis had resigned from his position as Secretary of State. The BBC – who first reported it – later retracted their announcement and confirmed Mr Lewis has not yet gone.
However, Mr Lewis is understood to be one of a number of Cabinet Ministers who told Boris Johnson he should step down.
It comes as Johnson’s long-term ally Michael Gove has been sacked by the Prime Minister, while Attorney General Suella Braverman, previously a staunch supporter of Mr Johnson, put her name into the ring if there is a leadership contest.
Sources told the PA news agency the Northern Ireland Secretary believes Mr Johnson’s position is "now untenable" and joined a delegation of other ministers, including the Chief Whip, who urged the embattled leader to resign.
Mr Lewis has consistently remained one of Mr Johnson’s most loyal lieutenants and the reported move comes as a blow to the Prime Minister.
The Secretary of State’s predecessor Julian Smith said the PM should “take the lead in a responsible transition to ensure stable government for our country”.
Mr Shapps, the Transport Secretary, who was key in the Prime Minister's fight for survival during partygate, was also understood to be part of the group, as was Welsh Secretary Simon Hart, who has now resigned from the Cabinet.
Business Secretary Kwasi Kwarteng is also understood to believe the Prime Minister now has to go.
Reports even suggested Nadhim Zahawi, who was only appointed Chancellor on Tuesday, was among those taking part in the showdown with Mr Johnson.
The latest developments come as SDLP leader Colum Eastwood earlier claimed he would be “astonished” if Boris Johnson remained in charge of his party by Wednesday evening.
In a tweet, the Foyle MP said he has picked up on the “mood around here” in Westminster and added: “I would be astonished if Boris is still Prime Minister by tonight.”
DUP MP Sammy Wilson earlier backed Mr Johnson to remain as prime minister and said “stability” is now needed in government instead of the "self-indulgence” of a leadership contest.
Speaking to GB News, Mr Wilson said: “What we need is stability, not this self indulgence of who should lead the Conservative party.”
He added: “We've got a prime minister, he was elected [...] with a strong majority, he is a flawed man. We know that in Northern Ireland, he’s made promises he can’t keep. Nevertheless, if you look at the overall picture, the country can’t afford this indulgence at the moment.”
Mr Johnson has insisted he will stay in office. At Prime Minister's Questions, he said he had a "colossal mandate" from the 2019 election and would "keep going".
Labour's Sir Keir Starmer said those staying in post were "nodding dogs" who were "defending the indefensible".
Chancellor Rishi Sunak and Health Secretary Sajid Javid quit within 10 minutes of each other, followed by a flurry of junior ministers and aides.
In a resignation statement after PMQs, Mr Javid said "treading the tightrope between loyalty and integrity" had become "impossible in recent months".
He added: "At some point we have to conclude that enough is enough. I believe that point is now."
Meanwhile, Stormont health minister Robin Swann said it appears it’s time for change.
Speaking to the BBC’s Good Morning Ulster programme, he said: "I think when it comes to the point where either a team captain or a leader loses the changing room, there has to be a decision made by those who remain on the team on who is best to lead it."
Sinn Fein’s Michelle O’Neill on Tuesday said Boris Johnson had been “bad for the north”
"He has failed workers and their families struggling with the cost of living," she said. "He has failed victims of the conflict and their families."
Sir Jeffrey did not mention Mr Johnson directly, describing the Conservative Party's leadership and "those who occupy cabinet positions" as a party matter.
"Our focus remains on working to see the removal of the Irish Sea border brought about through the NI Protocol," he said.
Here is the list of the 45 people who have left the Government in the past 24 hours:
1. Sajid Javid, health secretary, on July 5 2022
2. Rishi Sunak, Chancellor of the Exchequer, on July 5 2022
3. Alex Chalk, Solicitor-General, on July 5 2022
4. Jonathan Gullis, parliamentary private secretary at the Northern Ireland Office, on July 5 2022
5. Virginia Crosbie, parliamentary private secretary at the Welsh Office, on July 5 2022
6. Nicola Richards, parliamentary private secretary at the Department for Transport, on July 5 2022
7. Saqib Bhatti, parliamentary private secretary at the Department of Health, on July 5 2022
8. Andrew Murrison, trade envoy to Morocco, on July 5 2022
9. Theo Clarke, trade envoy to Kenya, on July 5 2022
10. Bim Afolami, Conservative Party vice-chairman, on July 5 2022
11. Laura Trott, parliamentary private secretary at the Department for Transport, on July 6 2022
12. Will Quince, parliamentary under-secretary of state at the Department for Education, also July 6 2022
13. Robin Walker, minister of state at the Department for Education, on July 6 2022
14. Felicity Buchan, parliamentary private secretary at the Department for Business, Energy & Industrial Strategy, on July 6 2022
15. John Glen, minister of state at the Treasury, on July 6 2022
16. Victoria Atkins, minister of state at the Ministry of Justice, on July 6 2022
17. Jo Churchill, parliamentary under-secretary of state at the Department for Environment, Food & Rural Affairs, on July 6 2022
18. Stuart Andrew, minister of state at the Department for Levelling Up, Housing & Communities, July 6 2022
19. Selaine Saxby, parliamentary private secretary at the Treasury, on July 6 2022
20. Claire Coutinho, parliamentary private secretary at the Treasury, on July 6 2022
21. David Johnston, parliamentary private secretary at the Department for Education, on July 6 2022
22. Kemi Badenoch, minister of state at the Department for Levelling Up, Housing & Communities, on July 6 2022
23. Julia Lopez, minister of state at the Department for Digital, Culture, Media & Sport, on July 6 2022
24. Lee Rowley, parliamentary under-secretary of state at the Department for Business, Energy & Industrial Strategy, on July 6 2022
25. Neil O’Brien, parliamentary under-secretary of state at the Department for Levelling Up, Housing & Communities, on July 6 2022
26. Alex Burghart, parliamentary under-secretary of state at the Department for Education, on July 6 2022
27. Mims Davies, parliamentary under-secretary of state at the Department for Work & Pensions, on July 6 2022
28. Duncan Baker, parliamentary private secretary at the Department for Levelling Up, Housing & Communities, on July 6 2022
29. Craig Williams, parliamentary private secretary at the Treasury, on July 6 2022
30. Mark Logan, parliamentary private secretary at the Northern Ireland Office, on July 6 2022
31. Rachel Maclean, parliamentary under-secretary of state at the Home Office, on July 6 2022
32. Mike Freer, parliamentary under-secretary of state at the Department for International Trade, on July 6 2022
33. Mark Fletcher, parliamentary private secretary at the Department for Business, Energy & Industrial Strategy, on July 6 2022
34. Sara Britcliffe, parliamentary private secretary at the Department for Education, on July 6 2022
35. Ruth Edwards, parliamentary private secretary at the Scottish Office, on July 6 2022
36. Peter Gibson, parliamentary private secretary at the Department for International Trade, on July 6 2022
37. David Duiguid, trade envoy for Angola and Zambia, on July 6 2022
38. James Sunderland, parliamentary private secretary at the Department for Environment, Food & Rural Affairs, on July 6 2022
39. Jacob Young, parliamentary private secretary at the Department for Levelling Up, Housing & Communities, on July 6 2022
40. James Daly, parliamentary private secretary at the Department for Work & Pensions, on July 6 2022
41. David Mundell, trade envoy for New Zealand, on July 6 2022
42. Danny Kruger, parliamentary private secretary at the Department for Levelling Up, Housing & Communities, on July 6 2022
43. Michael Gove, Secretary of State for Levelling Up, on July 6 2022, sacked for reportedly suggesting Boris Johnson should resign
44. Simon Hart, Secretary of State for Wales, on July 6 2022
45. Edward Argar, minister of state at the Department of Health and Social Care, on July 6 2022