Today marks the 28th anniversary of the Sydenham murder of private eye Daniel Morgan – and his family are still waiting for justice in one of the UK’s most notorious criminal cases.

On March 10, 1987, Mr Morgan, who ran Southern Investigations detective agency, was found in the car park of The Golden Lion pub in Sydenham with an axe in his head.

In the 28 years that followed, the crime has been linked with allegations of corruption in the Metropolitan Police, and questions have been asked about the involvement of reporters at the News Of The World in tailing one of the officers investigating the murder.

Five people were arrested in connection with the death in 2008 but the case collapsed after a string of supergrasses were discredited.

An independent panel was set up by Home Secretary Theresa May in May 2013 after numerous inquiries, at a cost of around £30m, failed to shed light on Mr Morgan’s murder.

Scotland Yard has admitted that corruption was a “debilitating factor’’ in the first investigation.

No one has been successfully prosecuted for the 37-year-old’s murder, despite five police investigations.

Alistair Morgan, Daniel’s older brother, said: “I want it all out there in the public domain.

“It’s been a long haul and there’s still a lot more that needs to come out about this case.”

The Daniel Morgan Independent Panel, which has been chaired by Baroness Nuala O’Loan since July 2014, is also looking into how Mr Morgan’s family were treated by the police and criminal justice system, issuing an appeal yesterday.

Alistair and his mother visited the Golden Lion pub in 2007 to lay flowers and renew their battle to find out who murdered him

Mr Morgan added: “Progress has been made which is heartening but there’s an awful lot to do and issues to look at. It’s a two-sided problem this. We’ve got the issue of the explanation of the policing and there’s a lot to look at there alone. But also we have got the News of the World aspect of the case which is very troubling too.

“I believe that if we had had a judicial inquiry like we wanted in 2004, it might well have prevented the hacking scandal.”

In 2011, the Metropolitan Police acknowledged its “repeated failure” to tackle corruption within the force, which helped protect those responsible for the murder from being brought to justice.

Mr Morgan said: “It bugs me enough to keep on pursuing this for justice.”

Baroness O’Loan, who previously investigated the police’s handling of the 1998 Omagh bombing, has now called for anyone who believes they may have information to come forward.

She said: “As we approach the 28th anniversary of Daniel Morgan’s murder, the panel would like to hear from anyone who believes they may have information which is relevant to its work.

“If you believe you have any such information, no matter how insignificant it may seem, please contact the panel by email at contactus@dmip.gsi.gov.uk.”

Under its terms of reference, the panel is addressing alleged connections between police officers, private investigators and journalists at the News of the World and other media involved in the case.

It is also examining documents from a number of government and non-government organisations, including the police and the Crown Prosecution Service (CPS).