The IOPC has concluded there are no new avenues of investigation which could result either in criminal or disciplinary proceedings.

It means the former Met Commissioner, Cressida Dick, will not face future disciplinary proceedings over the matter.

Contrary to MOPAC’s assessment of her conduct regarding the case, however, the IOPC has assessed that she may have breached police standards of professional behaviour by not providing full and exceptional disclosure to the Daniel Morgan Independent Panel (DMIP) sooner. It was nonetheless not to the extent which would justify disciplinary proceedings.

The IOPC said there is “no evidence to indicate Commissioner Dick intended to protect corrupt officers” and found that she had acted with a genuine belief to protect the information.

However, it said that she may have got the balance wrong – and should have given greater priority to her duty to provide full disclosure to the panel.

Daniel Morgan was murdered in south London on March 10 1987. The official inquiry subsequently accused the Met of multiple failings across 34 years and “a form of institutional corruption” for concealing or denying failings over the unsolved murder.

Following the publication of the Daniel Morgan Panel Inquiry report (DMIP) last June, the IOPC asked the appropriate authorities to assess if any conduct matters should be recorded.

MOPAC and Hampshire had said they would not be recording the conduct of any officer or former officer last year, and the MPS said the same in March of this year.

After assessing the conduct of 50 officers, the IOPC has now said they will not be taking further action in any case.

In addition, however, to its assessment of Dame Cressida Dick, it further disagreed with the MPS assessment regarding former Assistant Commissioner John Yates.

While the MPS had said reflective practice would be an appropriate response, the IOPC found an indication that he may have breached standards by failing to take action against the senior investigation officer, DCS Dave Cook (the latter’s actions had led to the exclusion of key witness evidence of three defendants for Mr Morgan’s murder).

Given AC Yates’ retirement in 2011, disciplinary proceedings cannot be brought and as any investigation would not provide further information that in the DMIP report, the IOPC cannot use its ‘power of initiative’.

Sal Naseem, IOPC regional director for London, said: “From the first to last investigation into Daniel Morgan’s murder there were failures to adequately challenge and investigate allegations that officers had acted corruptly.  

“The circumstances of these matters must serve as a salient reminder to the Metropolitan Police and the police service more widely, of the importance of being constantly vigilant in challenging improper and corrupt behaviour swiftly, firmly and robustly.”  

In a statement, Mr Morgan’s family said they are “disappointed but not surprised” by the IOPC’s review and questioned why it took so long for the watchdog to produce “no more than a rather poor shadow of the findings” of the panel last year.

Dame Cressida said she disagreed with the IOPC’s analysis that she might have breached standards, insisting she and her team acted “professionally, flexibly, expeditiously, diligently and with integrity in a challenging, unprecedented and complex task”.

She said the watchdog had recognised “that everything I did was for a legitimate purpose”.

She added that she “deeply” regrets “that no one has been brought to justice for Daniel’s murder”, and regrets “everything the Met or any of its members have done which has added to the pain of Daniel’s family of losing Daniel in such terrible circumstances”.