To say that Nicholas Knatchbull was born into a world of privilege only to have blown it is something of an understatement.

A close childhood friend of Princes William and Harry, the young aristocrat stood to inherit one of the most eminent titles in the English peerage, along with a Grade I-listed Palladian stately home set in 620 acres of prime Hampshire farmland and a tidy £100million fortune.

He is the King's godson and his great-grandfather was Lord Louis Mountbatten, Prince Philip's uncle who was assassinated by an IRA bomb.

But rather than breezing his way through Eton before eventually becoming the fourth Earl Mountbatten of Burma, instead he went spectacularly off the rails - earning national notoriety for his epic partying and an enormous appetite for recreational drugs.

He even shaved his head and got tattoos.

So wayward was Knatchbull and so repeatedly did he mess up that his furious father finally cut him off completely and removed his name from his will - which saw Nicholas spend his twenties and early thirties in a series of dingy flats, drug dens and squats among some very unsavoury people.

Now however the Daily Mail can reveal a dramatic twist in the tale: the longtime addict, now 44, married with two children and 15 years' sober, has recently moved back into his childhood home, the Broadlands Estate.

And, most remarkably of all, he is even understood to have been restored to his status as heir to Broadlands.  

One source close to the family said: 'Even in a country with a long history of debauched and outrageous aristocrats, Nicholas Knatchbull was in a class of his own for scandal.

'So his comeback to be restored to not just living here but being reinstated on the will is simply astonishing. He had been unmentionable here for two decades.'

Knatchbull had seemed destined from birth for the very highest reaches of British society.

He made childhood appearances on the balcony at Buckingham Palace and was assigned to show Prince William the ropes when he started at Eton.

His great-grandfather, the legendary Lord Louis Mountbatten, was the last Viceroy of India with whom King Charles shared such an exceptionally close bond that he referred to him as 'Honorary Grandfather'.

His mother Penelope was a close friend and confidante of the late Queen and the carriage-racing partner of Prince Philip. She was the only one of his friends invited to his funeral due to coronavirus restrictions.

And as a boy Nicholas enjoyed holidays with William, Harry and Princess Diana.

The world, it seemed, was young Nicholas's oyster. But then he discovered drugs - and soon his life unraveled completely.

As a young man Nicholas, who then had the courtesy title of Baron Brabourne, was hopelessly addicted to heroin, cocaine and crack cocaine and also repeatedly consumed LSD, ketamine and cannabis.

The family tried everything to change his ways.

He underwent treatment twice for drug addiction at the renowned Cottonwood centre in Tucson, Arizona, and was also an inpatient at the Farm Place Clinic in Surrey and the Stepping Stones Addiction Centre in South Africa.

Nicholas, living in sordid squats in London and Southampton, was even at one point sectioned under the Mental Health Act for his own safety after he 'disappeared' from the Priory clinic where he was being treated for his addictions.

He was banished from Broadlands, the 60-room mansion in Romsey, Hampshire, where both the Queen and Philip and later Charles and Diana had spent parts of their respective honeymoons.

He was repeatedly threatened with disinheritance - and eventually the threat was carried out. It was expected that it would now be left to his sister, Lady Alexandra Hooper, the goddaughter of Princess Diana.

The journey back to the family fold would be a long one - one that has only finally concluded this year.

This road to redemption began with him finally getting off drugs.

Nicholas is now said to be 15 years clean of the Class As which had almost destroyed him, following those repeated stints in various rehab facilities which cost hundreds of thousands of pounds.

But his family remained wary of believing the change would last. There were abiding trust issues.

The next stage towards him being accepted again was him finally settling into a serious and sustained relationship.

Admittedly his choice of partner was not the conventional blue-blooded debutante type that might have been expected initially.

Instead Ambre Pouzet was an alternative cabaret performer from France who amusingly described herself as a 'mer-lesque' artiste - a joke around her somewhat raunchy turn which saw her dress as a mermaid under the stage name Saint-Clare.

There followed a two-and-a-half-year engagement.

And in May 2021 when they wed, the ceremony was - tellingly - held at Broadlands.

That wedding was quite different from Nicholas's sister Alison's 2016 nuptials, when she was walked down the aisle by the then Prince Charles and guests included the Queen and Prince Philip.

That held for Nicholas and Ambre, a civil ceremony, was much more low key. But nevertheless it signalled a further thawing for relations with his family.

And soon the couple were a family themselves: Ambre had a son, Alexander, in 2022

They were initially allowed to live in a cottage adjoining the estate boundary. Then, after having their first child, they then moved to a larger converted barn, which was also located just outside the estate's boundary.

Nicholas was given gainful employment on the estate - as gardener, as if he were from the downstairs rather than upstairs classes.

He would be out in all weather, tending the various landscaped gardens, parks and pleasure grounds which are surrounded by wilder grasslands, woodlands and farmed land.

And last year Ambre had their second child, Endora, when the young family were finally allowed to move into Broadlands itself, the Daily Mail has learned.

A former neighbour near their barn home said this week: 'The last time I saw Nicholas was about six months ago and he told us where he was going to be moving - into Broadlands.

'It was quite a surprise given everything we knew - but it was true.

'He's now behind the main gate and the security fence so we never see him any more.'

Nicholas's road to redemption had been a long and arduous one but becoming a father seems to have been instrumental to the reconciliation with his family.

A source said: 'It was decided to bring Nicholas back into the family because he's proved that he's a changed man.

'He's now married, has two children and has settled down a lot. The family feel that he's put his past behind him and that the time is right for all of them to move on.

'He's living back in the main house with his family. Nicholas has gone through a lot and it's good to see that he's got his life back on track. We are all happy for him.'

Another source at Broadlands said: 'We were recently told that he is now going to inherit the title of Earl Mountbatten and the estate after all.

'His mother particularly wanted him back and he's helping her a lot because she had been running the estate more or less on her own and it's not been easy for her.

'Nicholas has proved that he's not the person that he was and it's wonderful to see him living back at the main house at Broadlands where he belongs.

'But it's an amazing turnaround. He's gone from being a hopeless drug addict to potentially the head of a historic family once again.'

Nicholas's parents, Lord and Lady Mountbatten, 78 and 73 respectively, have been separated since 2010 when the then-Lord Romsey left the marital home to live in the Bahamas with a new partner, the vivacious fashion designer Lady Nuttall.

That relationship however didn't endure and just a year later he returned to England - initially not to the main house but a smaller property on the estate. He was eventually permitted to move back into the Broadlands main house.

Lord Mountbatten is understood to have suffered a prolonged period of ill health which has further intensified the demands on Lady Mountbatten around running the estate - again a reason why Nicholas's return has been so appreciated.

And their happiness over his rehabilitation is a welcome upturn in fortunes for a family which has had its share of tragedies.

Nicholas's youngest sister Leonora died from kidney cancer in 1991 aged just five - when he was ten.

Her diagnosis came while the Knatchbulls were on holiday with the then-Prince Charles and Princess Diana.

Lady Mountbatten said following Leonora's death: 'My faith was tried at one stage – but it is stronger now. I accepted her death intellectually, but my heart didn't.'

The family also had to endure the notorious murder of the first Lord Mountbatten at the hands of the IRA in 1979 in which Norton's brother was also killed.

Despite now helping to run the Broadlands estate and returning to his place within the family, Nicholas continues to have alternative interests which may seem incongruous for the aristocracy.

He uses the names 5D Nick, Deep N Beeper and Onepacman for making a range of electronic music.

He hosts a podcast called 'Beeping Deeply' which states that it is designed to showcase his 'music nerd level knowledge across multiple genres'.

Nicholas's social media is filled with videos of him in the studio making music and one even has a picture of his godfather, King Charles behind the decks wearing headphones and sunglasses.

He has also released two sci-fi novels and sells and makes digital art.

Our source said: 'He's a very down to earth man, easy to talk to and you'd never guess that he was an aristocrat and so well connected.'

Some of those connections are being reestablished, it seems.