Investigating Diana: Death in Paris will tell for the first time the full story of two police investigations into her death - one by the French Brigade Criminelle in 1997, and one by the Metropolitan Police in 2004.
The four-part series will be told as a gripping forensic and police procedural, exploring the 1997 crash in Paris that killed Princess Diana and led to endless speculation in the press and online about what had really happened.
Many of the detectives from both France and England featured in the series will be speaking about the case for the first time and will share how they managed to separate fact from fiction while faced with unreliable witnesses and shaky memories.
It also looks at the public's insatiable appetite for answers about the case and the conspiracy theories that mushroomed in the early days of the internet.
Shaminder Nahal, head of specialist factual and commissioning editor at Channel 4, said: “This utterly compelling series explores in forensic detail what happened in the investigations following the death of Princess Diana - what it was like for the detectives working on a huge global news story that was not just a tragedy for the families involved, but a massive internet phenomenon too.
"In the end the series asks profound questions about ourselves as a society, and the nature of truth.”
Princess Diana's infamous 1995 interview with Martin Bashir was recently declared off limits for airing again by the BBC following an investigation into the unethical tactics used to secure the Panorama exclusive.
BBC boss Tim Davie said: “Now we know about the shocking way that the interview was obtained, I have decided that the BBC will never show the programme again; nor will we license it in whole or part to other broadcasters.
“It does of course remain part of the historical record and there may be occasions in the future when it will be justified for the BBC to use short extracts for journalistic purposes, but these will be few and far between and will need to be agreed at executive committee level and set in the full context of what we now know about the way the interview was obtained.
“I would urge others to exercise similar restraint.”
Watch: Prince Harry keeps a photo of Princess Diana meeting Nelson Mandela on the wall