THE sister of a black man who died in police custody 15 years ago condemned the police complaint watchdog’s procedures today after it gave an “unreserved” apology for its failings.

Sean Rigg died of a heart attack in 2008 after police restrained him while he was having a mental health emergency and then kept him in a cage in the back of a police van before taking him to Brixton police station.

The case was investigated by the Independent Police Complaints Commission (IPCC), but its findings were at odds with evidence given to a jury at an inquest into his death.

In 2013, the IPCC apologised to Mr Rigg’s family for its failings, but the investigation dragged on for another decade under the commission’s successor watchdog the Independent Office for Police Conduct (IOPC).

Three of the five Metropolitan Police officers involved in restraining Mr Rigg sued over delays in the investigation and were given apologies and paid compensation, although Mr Rigg’s family was not informed.

An apology for further failings has now been given by the IOPC.

But Mr Rigg’s sister Marcia Rigg said that 15 years after her brother’s death “the never-ending trauma and painful impact continues to haunt me, through no fault of my own or my family.

“In my view and that of many families and the public generally, there continues to be zero confidence in the investigative and judicial process [and] no justice, even with damming evidence and countless reviews.

“[This proves] that the whole judicial system in the UK is fundamentally flawed — institutionally racist, corrupt and a national public scandal.”

The family has received helped from lawyers’ group Inquest, which supports the relatives of people who die in police custody.

Inquest director Deborah Coles said: “The justice system has completely failed Sean Rigg and his family.

“From the outset, there was a flawed investigation and a culture of obfuscation and denial from police officers responsible for the deadly restraint used against him.

“That any of those officers are then secretly compensated for delays is abhorrent.

“Fifteen years on and with no-one properly held to account, this case provides a stark reminder of how the mechanisms for holding police to account are not fit for purpose.”