The Prime Minister’s decision that Home Secretary Priti Patel did not breach the ministerial code comes nine months after concerns over her behaviour towards officials were first revealed.

Here is a timeline of how an inquiry into allegations of bullying by Ms Patel developed:

February 20

Reports emerged saying Ms Patel had sought to remove then Home Office Permanent Secretary Sir Philip Rutnam after a series of rows and that Sir Philip had raised concerns about her with the Cabinet Office.

The Times newspaper claimed multiple sources inside the Home Office accused Ms Patel of “bullying” and “belittling” officials in meetings and creating an “atmosphere of fear”.

Allies defended Ms Patel, while the Home Office said no formal complaints had been made against the Cabinet minister.

February 24

The Home Office provided a statement saying Ms Patel and Sir Philip were “deeply concerned about the number of false allegations appearing in the media”.

It came amid a report from the Sunday Times that intelligence chiefs did “not trust” Ms Patel and had limited intelligence-sharing with her, prompting a strong Government denial.

Meanwhile, then Cabinet Secretary Sir Mark Sedwill told all civil servants that advice they provide for ministers and “any debates” around it should remain “private”.

February 29

Sir Philip quit his post and launched a blistering attack on Ms Patel, saying he had been the target of a “vicious and orchestrated briefing campaign” which he accused the minister of orchestrating.

He announced he would be pursuing a claim for “constructive, unfair dismissal” in the courts.

March 2

It was revealed the Prime Minister had asked the Cabinet Office to “establish the facts” following allegations that Ms Patel has breached the ministerial code.

Cabinet Office minister Michael Gove confirmed the action following an urgent question from then Labour leader Jeremy Corbyn.

Mr Gove said Ms Patel “absolutely rejects these allegations”.

March 3

Then Labour shadow home secretary Diane Abbott called on Ms Patel to stand down while complaints against her were looked into.

March 4

The Prime Minister said he was “sticking by” his beleaguered Home Secretary in a public show of support.

April 20

Civil servants’ union the FDA revealed Sir Philip had submitted his claim for “constructive dismissal” to an employment tribunal.

April 29

Labour demanded the inquiry into allegations that Ms Patel bullied officials be made public “as soon as possible”.

There had been no official comment on whether the inquiry had concluded, but multiple reports said she had been cleared of breaching the ministerial code.

July 11

Labour reiterated calls for the inquiry report to be published immediately.

It came after reports in The Times of a “stand-off” between senior officials and political aides over the publication of the inquiry’s findings.

October 22

Cabinet Secretary Simon Case declined to state whether the report would ever be published, saying it was up to the Prime Minister to draw conclusions from the probe and decide whether to make it public.

November 17

Lord Sedwill, now former head of the civil service, said the investigation into the allegations against Ms Patel was “with” the Prime Minister, saying he understood Mr Johnson had been given sight of the findings.

November 19

The BBC said a draft report concluded in the summer that Ms Patel had broken the rules on ministers’ behaviour.

November 20

Sir Alex Allan, Mr Johnson’s adviser on ministerial standards, resigned after the Prime Minister contradicted his advice by judging Ms Patel did not breach the rules despite being found to have bullied staff.

Sir Alex said the Home Secretary had not always treated civil servants with “consideration and respect” and he had concluded that her approach on occasions “amounted to behaviour that can be described as bullying in terms of the impact felt by individuals”.

Ms Patel said she was “sorry that my behaviour in the past has upset people”.