image copyrightMetropolitan Policeimage captionDaniel Morgan was found dead in a pub car park in 1987
The Met Police was institutionally corrupt in the way it concealed or denied failings over the unsolved murder of Daniel Morgan, a report says.
The force's first objective was to "protect itself" for not acknowledging its failures since the 1987 murder of the private investigator, chair of an independent panel Baroness O'Loan said.
Mr Morgan's family and the public are owed an apology, the report concluded.
He was killed with an axe in the car park of a pub in south-east London.
Despite five police inquiries and an inquest, no-one has been brought to justice over the father of two's killing, with the Metropolitan Police admitting corruption had hampered the original murder investigation.
The panel found the family of Mr Morgan "suffered grievously" as a consequence of the failure to achieve justice for them.
It criticised the "unwarranted assurances" they were given, the misinformation put into the public domain, and a failure "to acknowledge professional competence, individuals' venal behaviour, and managerial and organisational failures".
"The Metropolitan Police also repeatedly failed to take a fresh, thorough and critical look at past failings," the report said.
"Concealing or denying failings, for the sake of the organisation's public image, is dishonesty on the part of the organisation for reputational benefit and constitutes a form of institutional corruption."
- Timeline: Daniel Morgan axe murder
In a statement through their lawyer, Mr Morgan's family said: "We welcome the recognition that we – and the public at large – have been failed over the decades by a culture of corruption and cover-up in the Metropolitan Police, an institutionalised corruption that has permeated successive regimes in the Metropolitan Police and beyond to this day."
Home Secretary Priti Patel told the Commons the report was "deeply alarming" and revealed a "litany of mistakes" by the Met Police.
She said the behaviour of the force "irreparably damaged the chances of successful prosecution".
Mr Morgan, from Llanfrechfa near Cwmbran in south Wales, died in the car park of the Golden Lion pub in Sydenham on 10 March 1987.
image copyrightPA Mediaimage captionPanel members Nuala O'Loan, Silvia Casale and Samuel Pollock read out a statement following the publication the report
Other failures criticised by the panel include procedural errors – the crime scene was not searched – and forensic work was of so poor a standard it was described by a senior officer in the second investigation as "pathetic".
"In many respects that investigation was not compliant with the policies and procedures in force at the time," the report says.
"From the beginning, there were allegations that police officers were involved in the murder, and that corruption by police officers played a part in protecting the murderer(s) from being brought to justice."
The panel received evidence from serving and retired officers that some officers who tried to report wrongdoing by other officers had been "ostracised, transferred to a different unit, encouraged to resign, or have faced disciplinary proceedings".
The panel also considered the possible impact of conflicting loyalties between the obligations of police officers who were freemasons, and their professional policing.