Mr Johnson finally lost control of power in No 10 following a string of resignations from ministers and aides, according to reports.
It follows a string of protests against his leadership.
Boris Johnson has spoken to Tory 1922 Committee chairman Sir Graham Brady and agreed to stand down, with a new Tory leader set to be in place by the party conference in October, a No 10 source said.
Reports suggest No 10 staff have been told the Prime Minister is leaving and his resignation is ready.
💥Hearing that staff in No 10 have been told that Boris Johnson IS resigning and his letter has been prepared. 💥
— Pippa Crerar (@PippaCrerar) July 7, 2022
The flurry of resignations began on Tuesday evening, led by Rishi Sunak and Sajid Javid who both quit their Cabinet posts.
Will Quince resigned as children and families minister, saying he could not accept being sent out to defend the Prime Minister on television with inaccurate information over the Chris Pincher row.
Mr Quince was one of the ministers sent on the airwaves to defend Mr Johnson’s position over Chris Pincher, who quit as deputy chief whip after allegedly assaulting two men while drunk at London’s Carlton Club.
The Prime Minister later acknowledged he had previously been informed of allegations against Mr Pincher dating back to 2019 and said he regretted keeping him in government beyond that point.
Mr Quince said he had received a “sincere apology” from Mr Johnson for being sent out with an “inaccurate” briefing about the Prime Minister’s knowledge of events.
Laura Trott quit as a ministerial aide, saying “trust in politics is – and must always be – of the utmost importance, but sadly in recent months this has been lost”.
Boris Johnson resigns as Prime Minister
The Prime Minister’s authority had already been damaged by a confidence vote which saw 41% of his own MPs withdraw their support in June.
The loss of crunch by-elections in Tiverton and Honiton and Wakefield later that month triggered the resignation of party chairman Oliver Dowden, while there is still lingering anger over coronavirus lockdown-busting parties in Downing Street.
Tory MPs are also uneasy about the Government’s high spending, high taxing approach as a result of the response to the pandemic.
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