Princess Diana and her companion Dodi Fayed in St Tropez in August 1997, a week before they died in a Paris car crash. Photo / AP
The search for the truth behind the crash that killed Diana, Princess of Wales, 20 years ago this month was part of a movement of challenging authority that a visiting British QC says can be traced to Brexit and the election of Donald Trump.
Michael Mansfield, in New Zealand to give a keynote speech - The Power of the People versus the People in Power - at the Criminal Bar Association conference today, represented Mohammed Al Fayed at an inquest following the death of his son and Dianain Paris.
Though Al Fayed is a wealthy businessman, he was an outsider in Britain. He wanted, said Mansfield, the same as ordinary families in many high-profile cases the QC worked on that challenged the establishment.
"He wanted what everyone wants, the truth," Mansfield told the Herald. "He had a view about what the truth would involve. He felt it would involve malpractice within the establishment, particularly the royal family.
"He certainly wanted exposed the various aspects of how Diana was treated, how Dodi was treated, both before, on the day of the death and afterwards.
"He wanted a bit of accountability. He was no different to any family I have represented. He wasn't popular at the time but through the process people began to sympathise."
Held a decade after the 1997 crash, the inquest jury concluded that Diana and Dodi Al Fayed were unlawfully killed by a combination of the driving of chauffeur Henri Paul, who also died, and the paparazzi.
Al Fayed believed the pairwere victims of a plot and refused to accept the verdict, saying as he emerged from the court: "The most important thing is it is murder."
Mansfield, 75, has acted in many of Britain's highest-profile cases including for the families of the Hillsborough disaster, the families of the victims of Bloody Sunday, the 'McLibel Two' - when McDonald's sued two activists - and many accused of involvement in IRA bombings.
During his 50 years of practice he has seen a movement that began in legal challenges to authority that he says can be traced to Brexit and Trump.
"I call the movement democratisation because I don't believe for most of my life I have lived in what I would regard as a true democracy. We have lived in an elite democracy in which there is a ruling class which have monopolised power throughout that period."
"There has been a gradual erosion which is rather more starkly illustrated by what has happened in the Brexit vote."
Some may not have realised what they were voting for, he said.
The political powerhouses have been thrown out of control in the UK, France and the United States. "Trump is just a wild card. Something like eight people dismissed in six months. They guy is just shooting from the hip. It is entertaining but he is going to cause long term quite a lot of social damage, I think."
Mansfield traced the movement to individuals and groups in the law in Britain recognising that the system had serious flaws and could not be regarded as infallible.
"That started with some cases I was doing, in particular the Guildford Four and the Birmingham Six. It was because ordinary people locked up refused to accept it."
The Birmingham Six won their second appeal after spending 15 years in jail.
A series of cases during the 1980s led to law changes to the way evidence could be collected and a criminal cases review commission was set up. New Zealand does not have one though one has been proposed by several politicians.
This disquiet translated to challenges to the adequacy of police investigations. Another landmark case he worked on was the racially-motivated murder of Stephen Lawrence, a black teenager killed while waiting for a bus in London.
Lawrence's parents argued it was a racist murder and that the police investigation was inadequate. Two of five suspects were charges and convicted 20 years later and a public inquiry ruled that the police at the time of the crime were "institutionally racist".
"That was an amazing conclusion for part of the establishment to say about another part of the establishment."
In earlier decades it was unimaginable that two ordinary people such as Lawrence's parents could fight and end up getting some justice and force big changes in the police service, Mansfield said.
Other examples include changes to safety regulations driven by the families of 51 people drowned in the 1989 Marchioness riverboat disaster and last year's Chilcot Report that resulted from lobbying by families of soldiers who fought in Iraq and claim they were injured in an unlawful war.
Mansfield, who studied philosophy and history as well as law, descends from a string of railway workers. He credits a 1950s television show, The Defenders, for his vocation.
"I watched each programme avidly. I thought wow, I'd like to do that. My father said you have got to be crazy, you'll never get there. We didn't have any means and he thought, 'stick to the railways mate."