The Duke of Sussex has described how returning from his final tour of Afghanistan triggered an “unravelling” but “no-one around me really could help”.

Harry, speaking in his new Heart of Invictus docuseries on Netflix, said he did not have a “support structure” to help him deal with his mental health struggles, which related back to the trauma of losing his mother Diana, Princess of Wales.

The duke, whose troubled relationship with the royal family has long been documented, said the impact of Diana’s death when he was 12 was never discussed and he finally sought therapy after “lying on the floor in the foetal position”.

The five-part documentary, which was launched in the UK at 8am on Wednesday, follows a group of former military servicemen and women on their road to the paralympic-style sporting competition Invictus, which Harry set up in 2014 for injured and sick military personnel and veterans.

In the second episode, entitled Invisible Injuries, Harry tells how he suppressed the trauma of losing his mother in a car crash – the 26th anniversary of which is on Thursday – but his return to the UK from his second frontline tour to Afghanistan in 2012 brought it all back.

“I can only speak from my personal experience, my tour of Afghanistan in 2012, flying Apaches,” he said.

“Somewhere after that, there was an unravelling.

“The trigger to me was actually returning from Afghanistan. But the stuff that was coming up was from the age of, from 1997, from the age of 12.

Prince Harry tour of duty in Afghanistan
Harry serving in Afghanistan in 2012 (John Stillwell/PA)

“Losing my mom at such a young age, the trauma that I had, I was never really aware of.

“It was never discussed. I didn’t really talk about it and I suppressed it like most youngsters would have done, but then when it all came fizzing out, I was bouncing off the walls. I was like ‘what is going on here? I’m now feeling everything as opposed to being numb’.

He added: “The biggest struggle for me was … no-one around me really could help.

“I didn’t have that support structure, that network or that expert advice to identify what was actually going on with me.

“Unfortunately, like most of us, the first time you really consider therapy is when you’re lying on the floor in the foetal position, probably wishing that you’d dealt with some of the stuff previously, and that’s what I really want to change.”

Harry on the day of Diana's funeral in 1997
Harry on the day of Diana’s funeral in 1997 (PA)

In a 2017 interview, Harry described how his brother, the now-Prince of Wales, had been a “huge support” and that William, with whom he has since fallen out, encouraged him to seek help.

The duke made a surprise appearance at a special US preview screening in California of the new five-part Netflix show which has been more than two years in the making.

He emerged to introduce it, telling the audience about the sacrifices that veterans and their families make while serving their country.

The series also charts the story of the Ukrainian team preparing for the competition in The Hague in 2022 against the backdrop of the Russian invasion.

It tells the story of paramedic Yuliia “Taira” Paievska who was training for the tournament when she was captured and held prisoner by Russian troops.

She was eventually released in the wake of global publicity at The Hague games about her situation.

Invictus Games – The Hague
A poster for Yuliia Paievska at Zuiderpark, The Hague, Netherlands (Aaron Chown/PA)

In the first 45-minute episode, Harry discusses how he never wanted to serve in the armed forces as a father.

The duke, who has two children Prince Archie and Princess Lilibet, is chatting during a hike in California with his friends, former Invictus competitors JJ Chalmers and David Wiseman, and says: “I’ve always had myself down as being the dad that I could never be serving while having kids. And you both did, right?

“It’s never the individual signing up – it’s the whole family signing up.”

Interviewed sitting in a chair facing the camera, Harry is asked to describe what he does.

He replies: “What do I do? Er… on any given day, I’m a dad of two under-three-year-olds.

“I’ve got a couple of dogs. (I’m) A husband. I’m founding patron of Invictus Games Foundation.

“There’s lots of hats that one wears, but I believe today is all about Invictus.”

Invictus Games 2016
Harry with former competitor JJ Chalmers at the Invictus Games 2016 (Chris Jackson/PA)

The Duchess of Sussex first appears in behind-the-scenes footage from November 2021 when the couple attended the Salute to Freedom gala honouring military veterans in New York.

Harry confides in his wife about his nerves as they walk hand in hand along a red carpet into the event, saying: “We haven’t done this in a while.”

Meghan, dressed in a red Carolina Herrera gown, replies: “I know.”

Harry adds: “My heart … I’m like (making a noise like a rapid heart beat) – I’m nervous.”

The duke is shown anxiously pacing around a room as he waits to take to the stage.

Meghan appears only briefly a few times, joining an outdoor group meeting with the couple’s Archewell staff, and taking to the stage to introduce Harry on the opening night in the Netherlands.

In one episode, Harry is seen with his eyes closed as he takes part in a breathing technique session with Invictus competitors, and, in a good luck video call, he tells Team UK to “f****** cry” if they feel like it during the tournament.

The duke also takes a night-time diving trip in Hawaii with US competitor Gabriel George where the pair are filmed watching the sea life underwater.

Harry is listed in the credits as an executive producer of the series, which was made in association with Harry and Meghan’s Archewell Productions.

It is directed by Orlando von Einsiedel and produced by Joanna Natasegara, who worked together on the Oscar-winning short The White Helmets.

Heart of Invictus forms part of the Sussexes’ multimillion-pound deal with Netflix – with their main output so far being last year’s controversial Harry & Meghan documentary.

The six-part series last December saw the duke and duchess shed light on their troubled life within the royal family and accuse Kensington Palace of lying at the Megxit summit to protect Harry’s brother William, and father Charles, now King.

Meanwhile, the couple’s other lucrative media deal – with Spotify – ended in June after one season of Meghan’s podcast Archetypes.

Heart of Invictus has been released in the run-up to next month’s Invictus Games which begins in Dusseldorf on September 9, with Harry set to travel to Germany for the start of the tournament, and Meghan joining later.