They remain two of the most monumental moments in modern royal history.

Tomorrow marks 28 years since Brits across the country woke up to the harrowing news that Princess Diana had been killed in a car crash in Paris.

The next major royal death would not come until September 2022 when Queen Elizabeth II passed away after 70 years on the throne.

Though both events were tragic, they are quite distinct. The Queen’s passing brought deep sorrow to many, but it was also acknowledged that she lived a long life, peacefully passing away at the age of 96 at Balmoral Castle.

While Diana’s was just 36 and the sudden death took the public completely by surprise leading to a mass outpouring of grief.

But despite the differences a new documentary about the day Princess of Wales died has uncovered a remarkable similarity between how the public reacted to the death of the people’s princess and then, 25 years later,  the UK’s longest serving monarch.

The documentary, which will air on Channel 5 this evening, will follow August 31 1997 hour-by-hour from the car crash –  which also killed Dodi Fayed and Dodi’s driver Henri Paul -in the early hours of the morning to when her body was taken to Chapel Royal in St James’s Palace on the evening.

One particularly poignant scene is when the jet carrying Diana’s body landed at RAF Northolt, in west London, before her coffin was placed in a hearse bound for a mortuary in London.

Queen Elizabeth II and Princess Diana together in 1993.  A new Channel 5 documentary has revealed a striking similarity between the deaths of Diana and the Queen 

Royal insider and journalist Tina Brown appearing on the new Channel 5 documentary – The Day Diana Died – set to air tonight 

The journey should have taken 40 minutes but the sheer volume of mourners pouring out onto the street to get glimpse of the motorcade slowed it right down. 

John Swain – who was a member of the Special Escort Group in the Metropolitan Police in 1997 – said: ‘We were going to straight down the M4 but we ended up using the A40 because once we got to the Polish war memorial roundabout we couldn’t go straight on because of the crowds.’

While former royal press secretary Dickie Arbiter said he was ‘flabbergasted’ by how cars and people were stopped watching the car from the central reservation barrier.

Mourners then began throwing flowers at the hearse as it passed them by.

Jayne Fincher – a royal photographer who followed Diana throughout her life and was at RAF Northolt to photograph her coffin described the moment as the beginning of a ‘pilgrimage’.

In similar scenes 25 years later the late Queen’s hearse departed the same airbase to  crowds of mourners.

It was a similarity which did not go unnoticed by the distinguished author Robert Hardman.

He said: ‘That’s when the first flowers started being chucked down. And it’s very similar to the reaction when the Queen flew in to Northolt from Scotland on a fairly wet evening but that didn’t stop the crowds and again people standing on the side of the road chucking flowers in vast numbers. 

Pictured: Princess Diana’s hearse (left) and Queen Elizabeth II’s hearse (right) One striking similarity between both the death of Diana and Queen Elizabeth is the public’s reaction where mourners poured out onto the street to throw flowers at the motorcade out of respect

Distinguished author Robert Hardman noted the similarity between the public’s reaction to both deaths. He said: ‘It’s very similar to the reaction when the Queen flew in to Northolt from Scotland on a fairly wet evening but that didn’t stop the crowds’

Princess Diana in June 1997. The Princess of Wales died in a car crash in Paris 28 years ago tomorrow 

‘Those are the moments I always find this is why monarchy is different.’

Indeed, royal insider and journalist Tina Brown goes on to explain why Diana’s sudden demise had such a profound impact on the public.

She said:’ The British people had really come to identify with this young girl which they had seen grow up they’d seen Diana through the years with all her ups and downs and she was still the people’s Princess. Their representative in the monarchy.’ 

‘Death of Diana was one of the greatest stories of the second half of the 20th century,’ Brown continued.

Elsewhere, the documentary also uncovers other details about that now notorious day.

Such as that Queen Elizabeth was reportedly clutching a hot water bottle when she was woken up to be told the news and how she had every television and radio removed from Balmoral to shield the young Prince Harry and William.

On top of this, the documentary noted that as the National Grid recorded a large power surge on that Sunday morning as millions of Brits switched on the television and flicked on the kettle at the same time.

A young Prince William and Prince Harry with their uncle Earl Spencer and father King Charles and their mother’s funeral. Diana’s funeral on September 6 1997 was watched by estimated 32million people in Britain

‘Typical British reaction is to put the kettle on console yourself and sit in front of the television.’ Brown said. 

Diana’s funeral on September 6 1997 was then watched by estimated 32million people in Britain which was over half of the entire population at the time and made it one of the most watched events in UK history.

And once again as Diana’s hearse made its final journey from London to Althorp crowds once again lined the street throwing flowers at the car.

The Day Diana Died will air on Channel 5 tonight at 9pm.