Couple who witnessed Princess Diana's death claim the crash was NOT an accident and that two cars involved have never been traced - as they reveal they now fear for their lives

• Robin and Jack Firestone reported seeing two dark cars at the scene
• The couple fear there could be reprisals after telling authorities what they saw 
• They witnessed aftermath of tragedy in the Pont de' l'Alma tunnel, Paris, on August 31, 1997
• Princess Diana, Dodi Fayed and their driver Henri Paul were all killed

A couple who witnessed the aftermath of the crash which killed Princess Diana say her death was 'no accident.' 

Robin and Jack Firestone claim they still live in fear for their lives after reporting seeing two dark and mysterious cars at the scene.

Princess Diana, 36, her lover Dodi Fayed, 42, and their driver Henri Paul, 41, all died in the Pont de' l'Alma tunnel, Paris, on August 31, 1997.

The Firestones told the Express they were on their way to their hotel in the back of a taxi when they drove into the tunnel just minutes after the collision.

They say they saw two 'formal' and 'awkwardly parked' cars which had stopped at the front of the Princess' Mercedes S280. 

But it was only the next morning they realised the woman inside the Mercedes was Diana. 

Robin and Jack Firestone believe Princess Diana's death was not an accident after witnessing aftermath of the crash

The property owners found a French police officer to report the mysterious cars they'd spotted.

Robin said: 'We went up to him and I said "listen we were in the tunnel last night and we need to talk to the police because there are things that we saw. 

'Without hesitation, he said they have enough witnesses. Don't worry about it.

'We were dumbfounded. One of the most famous women in the world is killed and they don't want to speak to witnesses.'

Despite being eyewitnesses, they claim they were stopped from giving evidence by French authorities and then the British because their testimony was so controversial. 

They were not even called to the first inquest which took place in London in January 2007.