Revealed: The truth behind the 'mystery car' conspiracy theory in Diana bodyguard death

He was, the conspiracy theorists asserted, the “mystery driver” who played the key role in the staged accident in which dark forces “bumped off” the greatest love Princess Diana ever had – her former bodyguard Barry Mannakee.

They speculate that as 17-year-old Nicola Chopp prepared to turn right out of Hermitage Walk onto Woodford High Road on the night of 14 May 1987, the driver of a “mystery estate car”, indicating to turn left from the main road into the same side street, somehow engineered what followed.

Ms Chopp, a trainee beauty therapist who had passed her driving test just six weeks earlier, pulled out into the high road into the path of a motorbike on which Mr Mannakee was pillion passenger.

The Suzuki’s driver, Mr Mannakee’s police colleague Sergeant Stephen Peet, reacted so quickly he was able to swerve and avoid hitting Ms Chopp’s red Ford Fiesta. But both men fell from the bike, and Mr Mannakee was flung against the side of Ms Chopp’s car, dying almost instantly from fatal spinal injuries.

Instead of stopping, the “mystery estate car”, it has repeatedly been said, carried on into Hermitage Walk and vanished, never to be found again.

The conspiracy theory became public in 2004 when US news channel NBC first aired video recorded by Diana’s voice coach Peter Settelen of the princess talking candidly about her private life.

“He was the greatest love I’ve ever had,” she said, clearly referring to Mr Mannakee, who had served as a Royal Protection Officer from April 1985 to March 1986. “I was quite happy to give it all up ... just to go off and live with him. And he kept saying he thought it was a good idea too.

“[But] it was all found out and he was chucked out [of royal protection]. Then he was killed. I think he was bumped off.”

And so began fevered speculation that because of his closeness to a still-married princess, Mr Mannakee was killed in a crash that was expertly staged by the secret services to look like a simple traffic accident in north east London.

This month, the conspiracy theory got a fresh boost when Channel 4 used footage from the private video recordings for its controversial documentary Diana: In Her Own Words.

Newspaper reports of the conspiracy theory always state that the “mystery estate car” – which is sometimes accused of dazzling Ms Chopp with its headlights – has “never been traced”.

Now, though, The Independent has tracked down the driver of the “mystery estate car”.

And it transpires that far from driving off, unknown and untraced, the driver, a retired GP:

The Independent has agreed not to name the former doctor, who is now elderly.

He admits his memory is failing, but conversations with him, his wife, and documents retained by the other two passengers in the car – a dentist friend and his wife – have allowed The Independent to piece together what they witnessed on the night of May 14 1987, and what they did afterwards.

All four people who were in the ex-doctor’s VW Passat estate that night are convinced that what they saw was nothing more than a tragic accident.

The retired doctor is adamant.

“I did not conspire to murder Barry Mannakee,” he told The Independent. “That’s laughable – about as laughable as it can get.

“It’s rubbish. Somebody’s making up a story to sell newspapers.”

The retired GP said he had never read newspaper reports that referenced a “mystery estate car” in the Barry Mannakee crash, and so had never felt the need to identify himself publicly.

He declared himself “flabbergasted” to learn that his vehicle had been implicated in a conspiracy theory that has been the subject of public debate for more than a decade.

And he burst out laughing at suggestions he was a member of the security services. On the contrary, he said, his asthma had prevented him from even doing National Service.

“My father was also a GP,” he added. “He took me round with him in the practice, and from then on I never wanted to be anything other than a GP."

The Independent has seen proof that he studied medicine at Cambridge before qualifying as a doctor. His friends describe him as “the epitome of the respectable middle class”.

They also confirm that they witnessed the crash at about 10.15pm, as they were on their way home from watching a play at the Greenwich Theatre in south-east London.

In his 1988 statement to the claims consultants, the GP said: “I was travelling at about 20-25 miles per hour as I was intending to turn left.

“I became aware of a vehicle emerging from Hermitage Walk, the road in which I intended to turn. The car was turning right.

“A motor cycle passed me just after I left the traffic lights and before the bus stop which is situated about halfway between the traffic lights and Hermitage Walk.

“When it [Ms Chopp’s car] was pulling out it did so at a normal speed, say 10-15 mph, for that type of manoeuvre.

“I seem to recall the bike pulling out towards the centre of the road in an attempt to avoid the car, but my recollection of the sequence of events is a little vague. I just remember seeing it [the motorbike] swerving.”

Having seen the crash, the GP’s statement confirmed: “I turned into Hermitage Walk and stopped and went to assist.

“The man lying to the right of the car [Mr Mannakee] appeared to be dead when I reached him. There was no movement.”

Over the years, some reports of the conspiracy theory – including The Independent’s in 2004 – have also suggested that at Mr Mannakee’s 1987 inquest, police investigators blamed the crash on the glare from the mystery car’s dazzling headlights.

This, of course, would be spookily similar to some reports of the Alma Tunnel car crash that killed Diana in 1997, which have claimed that driver Henri Paul was dazzled by a “major white flash” just before the accident.

The retired GP’s friends, however, have retained a local newspaper report of Mr Mannakee’s inquest, which would suggest the police investigators came to a rather less sensational view of how Ms Chopp might have failed to spot the motorbike.

The report states that a police accident analyst told the inquest that on a wet, drizzly night, “Ms Chopp may have been confused by various lights and lighting effects as she looked down the road. These included car headlights and their reflections in the damp road surface, the street lights, the traffic lights and the glow from the lighting at the Eagle Garage.”

The inquest recorded a verdict of accidental death. At a subsequent court hearing, Ms Chopp pleaded guilty to driving without due care and attention and was fined £85. Her insurance company settled the civil proceedings brought by Mrs Mannakee.

Ms Chopp has, however, repeatedly stated she does not believe herself responsible for Mr Mannakee’s death, saying she fears a possible conspiracy, although Sgt Peet, who was seriously injured in the crash, has always taken the view that it was a simple accident.

In terms of the actual details of the crash itself, however, there appears only one significant potential inconsistency between Ms Chopp’s testimony and that given by the occupants of the VW Passat.

In interviews given around 2004, 17 years after the crash, Ms Chopp is quoted as referring to the driver of the “mystery estate car” as being a woman wearing glasses.

The evidence now seen by The Independent, however, strongly suggests Ms Chopp made an honest mistake here, possibly misidentifying either the doctor’s wife or his friend’s wife – who were both in the back seat of the Passat – as the driver.

All the evidence – including that rediscovered by The Independent – points clearly to the “mystery estate car” being the VW Passat driven by the retired GP.

Ms Chopp has only ever referred to one estate car turning left in to Hermitage Walk, never two.

The retired GP’s statement to the claims consultants goes further and states that at the time of the crash there were in fact no other nearby cars on the high road – going in either direction – at all.

The doctor said: “I do not think there was any other vehicle going in my direction [north] or that anything other than the bike passed me.

“I do not recall any traffic going in the opposite direction until after the accident.”

His friend’s statement to police – given four days after the crash and now seen by The Independent – also states that as they approached the Hermitage Walk turning: “There were no other cars ahead of us.”

The possibility of a second car turning left behind the GP – but unnoticed by him and strangely unmentioned by Ms Chopp – is further ruled out by both the GP’s statement and his friend’s testimony to police.

Both documents confirm the men saw the accident happen straight ahead of them, before they turned off Woodford High Road into Hermitage Walk, and therefore before any unnoticed, following car could have started its turn.

In his 18 May 1987 statement to police, the friend said: “When we were about five to six car lengths south of the junction with the walk, I saw a collision between a motorcycle and a red, small, saloon car.”

The retired GP said in December 1988: “The motorcycle was quite well ahead of us when the car started to emerge. I was looking ahead and I saw the collision occur.”

Both statements also make clear that the motorcycle would have been well past the Hermitage Walk junction had Ms Chopp waited for a second car – that she has never mentioned – to turn left.

They are also consistent with Ms Chopp’s earliest evidence, given to the police hours after the crash, that she moved out of Hermitage Walk as soon as it was obvious the estate car was indeed turning left and had not just forgotten to turn its indicators off.

In interviews given more than a decade later, she appeared to contradict herself slightly, being quoted as saying the ‘mystery vehicle’ had actually passed her in Hermitage Walk after turning left.

This now seems impossible given how the evidence shows the retired GP’s VW Passat was the only other car in the vicinity, and it was still in Woodford High Road when the crash happened.

Some conspiracy theorists have gone as far as accusing Ms Chopp herself of being involved in the plot – something she and her family have had to deny.

The retired GP, his wife and friends also dismissed such a claim as ludicrous. The former doctor recalls seeing Ms Chopp “shaking and sobbing” in the immediate aftermath of the crash, and is convinced such deep distress would have been almost impossible to fake.

His wife added that she found it deeply implausible that any security service would take the risk of asking a 17-year-old to be involved in a killing.

The GP scoffed at the suggestion of any sort of conspiracy involving a staged accident to kill Mr Mannakee, especially as some reports suggest the 39-year-old, by then a sergeant with the Diplomatic Protection Branch, had intended to travel home by car that night.

It has been reported that Mr Mannakee only changed his mind and accepted a lift from Sgt Peet because he had been working late and wanted to get home to his family quickly.

The idea of a crash being staged in such circumstances was, the former GP said, “Extremely unlikely, to put it mildly.”

He and his wife, though, had watched the Channel 4 documentary.

“We found it very disappointing,” said the retired GP. “It didn’t add anything new.”