Even by the standards of Broadmoor, the high-security psychiatric hospital that has housed some of Britain’s most disturbed criminals, Tony Baekeland struck the staff as odd.

‘He somehow stood out,’ former nurse Colm Byrne tells the Daily Mail.

‘It’s hard to put your finger on it, but maybe it was because most of the patients were casually dressed whereas he always wore a proper shirt.

‘Or maybe it was just that we knew he was very wealthy so we looked at him a bit differently.’

Wealthy he certainly was. Good-looking and well-connected, too. As a little boy, his playmates had been Hollywood star Rita Hayworth’s children and Greta Garbo had attended his parents’ parties.

But none of that had stopped him carrying out the unthinkable crimes that saw him committed to Broadmoor, in the Berkshire village of Crowthorne, in the summer of 1973.

Hitting the headlines worldwide, they were later the subject of the best-selling book Savage Grace, published in 1985 and written by American authors Natalie Robins and Steven M. L. Aranson.

When this inspired the 2007 film adaptation, starring Julianne Moore as his mother Barbara and a young Eddie Redmayne as Tony, director Tom Kalin reported audiences sitting in silence as the credits rolled.

‘I thought, oh my God, I’ve failed completely,’ he said. But then he realised they had simply been left dumbstruck by what they had seen. It wasn’t just that Tony had murdered his mother, a glamorous American socialite. It was the reason for him doing so – the extraordinarily depraved act on her part that had driven him to matricide.

Even that wasn’t the full extent of it. Thanks to a set of influential do-gooders, he was eventually freed from Broadmoor and sent back to his native America, only to strike again before taking his own life in the spring of 1981.

Today, 45 years after his death, we can reveal the full horrifying story, including his previously undisclosed attempt to escape from Broadmoor, and the still- stranger part played by a Danish prince who married into the British Royal Family in his return to New York.

It was there that he was born in August 1946, into one of America’s wealthiest families. His great-grandfather was Leo Baekeland, the Belgian chemist who had invented Bakelite, the world’s first plastic, used in everything from radios and records to artificial limbs and atomic bombs.

Part of Tony’s vast fortune had been inherited by his father Brooks, an arrogant man with matinee-idol looks and what he called ‘f*** you money’.

‘That means I need not please or seek to please anyone,’ he boasted. Tony’s mother came from humbler stock, her father a depressive advertising executive from Boston who got into financial difficulties following the 1929 Wall Street Crash. In 1932, when Barbara was 11, he gassed himself with exhaust fumes from the family car, making it look like an accident so that his wife Nini would get the life insurance payout.

When Barbara was in her late teens, Nini used the money to move the two of them to New York’s swanky Delmonico hotel and schemed to find her daughter a wealthy husband.

With her flame-red hair, porcelain-white skin and captivating smile, Barbara was soon lauded as one of New York’s most desirable girls, modelling for Vogue, invited to Hollywood for a screen test, and attracting moneyed admirers.

Among them was Brooks Baekeland who was unaware at first that the ‘remarkably beautiful and staggeringly self-assured’ Barbara had recently been a patient of New York psychiatrist Foster Kennedy, who had been highly disturbed by whatever it was she told him in their sessions.

‘God forfend that they have a child!’ he said on learning Brooks and Barbara had wed in 1942.

As Kennedy had feared, their marriage was quickly beset by Barbara’s unsettling behaviour. On a skiing holiday to Switzerland, their startled friends saw her standing out in the snow by the light of a full moon, and howling like a wolf.

Back home, they were dining out one night when Brooks joked that, for a million dollars, he would sleep with the next woman who passed through the restaurant’s revolving doors, regardless of her age or looks.

‘If that’s the way you feel, I’ll just go with the first man who comes along in a car!’ replied Barbara. With that, she rushed out into the street, flagged down a vehicle with four young men in it and took off into the night.

‘A couple of hours later she came home, having evidently got rather cold feet,’ recalled a friend. ‘That was quite a crazy thing to do in New York City. Very crazy and very dangerous.’

As the Baekelands became fixtures of sophisticated society, Salvador Dali, Tennessee Williams and Dylan Thomas were among the guests at their home on the affluent Upper East Side, and the couple became known for their risque soirees.

At one, the men hid their top halves behind a screen and removed their trousers so that the women could guess which bottom half belonged to which husband.

The Baekelands were as unconventional in their parenting. One visitor to their home described them getting their young son to read aloud from the erotic writings of the Marquis De Sade. Another dropped the couple after witnessing Brooks’ obvious relish in describing how Tony had pulled the wings off a fly to see how it would affect its balance: ‘That kind of sadistic behaviour is quite common in children, but one seldom sees a father who thinks it is marvellous.’

As his parents swanned through a glamorous world of villas, yachts and aristocratic house parties, Tony seemed to be living a charmed life, but some saw signs of the trouble ahead.

On holiday in Italy with the Baekelands when Tony was about 12, a friend noticed him sitting alone on the rocks, playing with crabs. ‘He was sort of pulling them apart,’ she said. ‘In hindsight it was an awfully creepy little episode.’

By the time he reached adolescence, other stories were emerging. One friend, who shared a cook with the Baekelands in New York, heard that when his parents were away, the teenage Tony often picked up older boys on the streets and brought them home.

While this confirmed what Brooks, his father, had suspected for some time, Tony’s sexuality came as a terrible shock to his mother. ‘She fought against it ferociously,’ Brooks said. ‘She simply could never accept it.’

By 1963, the Baekelands were living mainly in Paris where Brooks fell in love with an English diplomat’s daughter who was 15 years his junior. When he pressed for a divorce, Barbara threatened to kill herself.

‘Faced with becoming a murderer for the sake of freedom, I gave up my girl,’ Brooks said.

Four years later, she inadvertently triggered the events that ultimately doomed their marriage.

As Tony and his parents spent the summer of 1967 in the fashionable Spanish resort of Cadaques, Barbara desperately encouraged his dating of a young woman called Sylvie. Constantly inviting her to their holiday villa, she impressed on her that marrying Tony would make her very rich.

This backfired when Sylvie began having an affair with Brooks instead. And this time he insisted the marriage was over. Before they separated, Barbara told Brooks that she had tried to help Tony ‘get over’ his attraction to men by hiring prostitutes to sleep with him. Since that didn’t work, she planned to take him to bed herself.

‘Don’t you dare do that,’ Brooks warned. But in the summer of 1969, she and Tony spent long periods together in a remote Majorcan villa and there Barbara initiated a sexual relationship with her 23-year-old son.

One friend received a telephone call in which she calmly announced what she had done. Another said she discussed the episode almost as though it were a form of therapy. But most disturbing was Tony’s own reaction.

‘I am f***ing my mother,’ he confided to one friend. ‘I don’t know what to do. I feel desperate.’

His mental state deteriorated dramatically afterwards. At a dinner party in New York, he streaked through the apartment. Enrolling in art classes, he painted sinister figures with blood dripping down their sides. Other pictures showed his mother decapitated, with serpents entwined around her neck.

‘It was obvious to me that he was very troubled, and it’s very surprising that he wasn’t in some sort of hospital,’ said his art teacher of the time.

Soon, even Barbara could not pretend that all was well and got him admitted to a private psychiatric clinic. He was soon back home because Brooks, who would go on to have another son with Sylvie, had cut Barbara’s allowance and refused to pay for Tony’s care himself.

Dismissing psychiatrists as practitioners of ‘abracadabra’, he insisted ‘Barbara’s son’, as he now referred to Tony, was ‘a kind of personification of Evil’. Soon relapsing, Tony beat Barbara unconscious with a heavy walking-stick one night and also knocked out her divorce lawyer when he came to her aid.

That led to a diagnosis of schizophrenia at the local hospital that recommended he should be sent to a private mental institution. But still Brooks refused to meet the costs.

In the early 1970s, Barbara and Tony moved to London where she somehow found the money to buy a penthouse flat on exclusive Cadogan Square, a five-minute walk from Harrods.

In these upmarket surroundings, Tony only seemed to get worse, culminating in a terrifying incident in the summer of 1972 when he attacked Barbara at the home of her friend Sue Guinness in nearby Kensington Square. Breaking free, she ran outside and attempted to escape but he seized her by her distinctive red hair and attempted to throw her in front of passing cars.

As she clung desperately to a gate, he repeatedly slammed it against her hand, breaking her thumb. Brandishing a carving knife, he then ran off, leaving her lying stupefied on the pavement with clumps of her hair missing.

Refusing to press charges after the police arrested Tony, Barbara consulted Dr Lindsay Jacobs, a psychiatrist recommended by a friend. He confirmed the diagnosis of schizophrenia, told her that it had been made worse because Barbara had not ensured he took his medication, and advised her that she was at serious risk. ‘Your son is going to kill you,’ he said.

The warning could not have been clearer but Barbara refused to listen. When it was clear that she wasn’t taking him seriously, Jacobs was so concerned that he phoned the police and asked them to put a guard on the Cadogan Square flat but was told they could do little until something actually happened.

Soon it did. On November 17, Barbara returned to the penthouse after lunch with a friend. That afternoon an argument broke out, Barbara fled into the kitchen and Tony picked up a knife and stabbed her. The wound was small but fatal, having severed a main artery.

When police arrived they found Barbara bleeding out on the kitchen floor while Tony was in the bedroom, phoning for a Chinese takeaway.

The following summer, he appeared at the Old Bailey, defended by John Mortimer, creator of the fictional barrister Rumpole. Convicted of manslaughter on the grounds of diminished responsibility, he was sent indefinitely to Broadmoor where he hatched his eccentric escape plan.

‘One day, the hospital censors intercepted a letter from an aircraft manufacturer,’ former nurse Colm Byrne told the Daily Mail.

‘It was asking Tony to confirm the delivery address for the helicopter he had ordered. No doubt his family name persuaded them of his ability to pay.’

Quite how Tony thought this plan might work is unclear. But although it demonstrated his disconnection from reality, this did not stop friends of the family campaigning for him to be freed.

Among them was Michael Alexander, a former Colditz prisoner who had been in the Scots Guards during the war. So too had Willie Whitelaw, the then Home Secretary, whose permission was necessary to secure Tony’s release.

Whether or not the old soldiers’ network played its part is not clear. But, in July 1980, Whitelaw made the extraordinarily misguided decision to discharge Tony.

In fairness to Whitelaw, Broadmoor psychiatrist Dr Thomas Maguire had opined that ‘his continued well-being indicates that there is now no need for in-patient treatment’. However, he was clear that this was only advisable if he had adequate ‘social supervision’ on his flight to New York and beyond.

Instead, the job of looking after him fell to a wholly unqualified stranger – his paternal grandmother’s friend Cecelia Brebner.

Although she lived in America, she was in England visiting a daughter who lived near Broadmoor and was asked if she would accompany him back to New York. Concerned about the wisdom of escorting a man on a long transatlantic journey who had murdered his own mother, she sought advice from an unlikely source.

This was her friend Prince George of Denmark, who had married the Queen’s first cousin, Viscountess Anson.

As far as the Daily Mail has been able to ascertain, the elderly military attache and diplomat had no expertise in mental health, but this didn’t stop him offering an opinion.

‘He thought it was a very altruistic thing to do, so I embarked upon it,’ explained Cecelia.

So it was that, on the advice of a minor royal, this kindly American and the murderer she hardly knew set off on a trip that was troubled from the start. Told that she would be leaving Tony in the care of a half-way house, she learned that there were no spaces in the promised facility and he would instead be staying with his grandmother Nini.

Far from being able to look after him, she had broken her hip and needed round-the-clock care herself. When they arrived at her Manhattan apartment, Tony immediately noticed a huge painting of his mother on her bedroom wall and ordered Nini to take it down. ‘I saw the look on this man’s face and I knew that I had done the wrong thing,’ said Cecelia.

Her fears were realised when, just six days after his release, he stabbed his grandmother eight times and inflicted on her multiple other injuries including a fractured collar bone and ribs.

When the police arrived, he told them she had refused to let him make a call to England so he had thrown the phone at her head, knocking her to the floor.

Realising he had injured her, he decided it would be kindest to put her out of her misery, and began attacking her with a kitchen knife, but she wouldn’t die. Miraculously, he had slashed through to bone each time. ‘I hate it when this happens,’ he told the police, as casually as though talking about a spilt drink.

He was taken to New York’s notoriously violent Rikers Island jail but, before he could be tried, he suffocated himself in his cell by putting a carrier bag over his head.

Like the murder of his mother, his death might have been averted had people heeded the many warnings over the years.

Much of the blame for that lies with Barbara and her conviction that nobody understood her son as she did. A belief from which she never wavered, it cost them both their lives.