No other woman has exerted quite so much influence in helping a timid boy to become as comfortable in the real world as in the privileged one into which he was born.
No one else lavished quite so much affection while daring to give the heir to the throne a clip round the ear on those rare occasions he broke her rules.
But then outside his own family Mabel Anderson is the only woman who has loved King Charles all his life.
She was his nanny as far back as he can remember – and before that too.
While his mother was preoccupied with affairs of state at home and abroad, it was nanny Mabel who was his first playmate, witnessed his first steps and helped put his first thoughts into words.
Such were the bonds between the two that he came to regard the young woman, who was almost the same age as the Queen, as a surrogate mother long after he had outgrown the Buckingham Palace nursery.
It was Mabel he ran to when he returned home from prep school and with whom he took all his meals at the Palace until he was 16. She was the one he would miss when he was homesick and lonely at Gordonstoun and in whom he would confide about the bullying he suffered there.
As an adult, he would fondly kiss Mabel goodnight whenever he was in residence and take breakfast with her in her quarters on the Palace’s third floor. When she retired, he hand-picked a grace and favour apartment on the royal estate at Windsor which he had redecorated at his own expense.
Then-Prince Charles is taken for a walk in his pram through the park on his third birthday by nanny Mabel Anderson
The extraordinary relationship between retainer and royal charge did not change after her retirement – if anything it deepened.
Each Christmas he would send a chauffeur-driven car to take her to Sandringham for the festivities, and she was invited on an Aegean cruise when he first publicly holidayed with Camilla Parker Bowles, ostensibly to keep an eye on William and Harry.
The princes were teenagers and didn’t really need a nanny, but their father wanted Mabel’s comforting presence for himself and to bring some stability into his (at the time) emotionally rocky life.
Last month Mabel turned 100 and, naturally, the King was on hand to share the special anniversary with her, breaking off from the crisis surrounding his brother Andrew’s arrest to travel to Windsor to deliver his personal congratulations along with the customary royal telegram.
No one was remotely surprised: the bond between the two has been one of the most enduring and intriguing in recent Royal Family history.
But there is another explanation. For Mabel was nanny not just to Charles but to all the Queen’s children and, while the King was undoubtedly her favourite, she doted on Andrew, the bonniest of all the royal babies.
She once perceptively noted that no nursery could contain two Prince Andrews. Mabel labelled him a ‘young imp’ for his pranks, which included tying sentries’ shoelaces together and pouring itching powder into the Queen’s bed. But however naughty Andrew was, the nanny adored him.
That devotion was to manifest itself many years later when she telephoned the then prince and asked tearfully if what she had heard on the radio was true – that he and the Duchess of York were to separate. When Andrew heard his old nanny’s voice he covered the receiver with his hand, turned to Sarah and asked with a trembling voice: ‘What shall we say to Mabel?’
Pictured in 1950: The then-Prince of Wales, aged two, watches a procession with Ms Anderson
Fergie, devastated by the collapse of her marriage and dispirited by what she saw as Andrew’s failure to measure up as a husband, replied: ‘Tell her what you want.’
More recently, with his anguish over the disgrace of his brother, a few hours with the uncomplicated Mabel must have been not just a tonic for the King but a welcome reminder of the uncomplicated days of his childhood nursery.
He once bitterly told Diana that the nanny was the only woman who really understood him.
With Mabel he could talk unflinchingly about his feelings and disappointments and know she would keep them in the strictest confidence. In return what she told him about her modest upbringing in rural Scotland – her policeman father was killed in the Blitz – provided the young Prince Charles with his first experience of life beyond Palace walls.
An early follower of innovations in diet, she also shaped his interest in food by introducing wholemeal bread to the royal dining table.
With her sensible clothes and carefully permed hair, Mabel exuded a reliable if prim kindness, but it was her strength of character that is widely regarded as a blueprint for Charles’s women later in life.
Indeed, the society portrait painter Suzi Malin went further, mischievously suggesting that Charles was so drawn to Camilla because of her passing resemblance to nanny Anderson.
Mabel was 22, two months older than her new employer, when she was engaged to work for the then Princess Elizabeth and her infant son soon after his birth in November 1948.
Pictured in 1950: Queen Elizabeth plays with Charles, aged two
Despite the future Queen announcing during her pregnancy that she was going to be her child’s mother ‘not the nurses’, two nannies were swiftly appointed at Clarence House, where the princess and Prince Philip then lived.
The senior and older of the two was Helen Lightbody who came on the recommendation of the Queen’s uncle and aunt, the Duke and Duchess of Gloucester, having brought up the present duke Richard and his elder brother Prince William, who later died aged 30 in a plane crash.
Mabel, by contrast, was a complete outsider. After the death of her father in a German bombing raid on Liverpool during World War Two, her mother returned to her Scottish roots, settling in Elgin. After leaving school and completing a two-year domestic science course where she learned to sew and cook, Mabel went into domestic service.
She had placed an advert in the ‘situations wanted’ section of a nursing magazine when she found herself summoned to London for an interview, where her quiet unassuming manner was a hit. She was hired on the spot.
The Palace nursery settled into a strict routine. The baby prince was woken at 7am sharp, washed, dressed and given breakfast. At nine he was taken down to the second floor for half an hour with his mother. The princess would try to see him again at teatime, watching him being bathed and put to bed.
As much as she wanted to be a normal mother, her presence in the nursery created an atmosphere of formality. Unsure of what to do, she would sit on a gilt chair which a footman brought in for her.
For the rest of the day the nannies were in charge, taking Charles to St James’s Park or to visit his great grandmother, the formidable Queen Mary whom he called ‘Gan-Gan’.
Much has been said and written about the absence of parental affection in Charles’s early life, sometimes by him. Inevitably perhaps with his parents distracted by their new roles as monarch and consort – and their natural emotional reserve – it was the nannies with whom the prince formed the deepest attachment.
Charles regarded Ms Anderson as a surrogate mother
The Queen’s former private secretary, the late Lord Charteris, observed drolly: ‘The Queen is not good at showing affection. She’d always be doing her duty.’
Reflecting on Charles’s early years he said: ‘He’d have an hour after tea with Mummy when she was in the country, but somehow even those contacts were lacking in warmth.
‘His father would be rather grumpy, about almost anything. And neither of them [Elizabeth or Philip] was there very much.’
Just before his second birthday the prince was joined in the nursery by a baby sister Anne, and the routine remained the same when Charles’s grandfather King George VI died in 1952 and the family moved across The Mall to Buckingham Palace.
The nursery, where the two women slept in the same suite of rooms as their royal charges and where a fire burned in the grate even in mid-summer, was a self-contained world of security in the vast and impersonal palace.
This was a mini-kingdom with its own rituals and the place where Charles was happiest. It was surely no coincidence that when he proposed to Diana it was in the nursery at Windsor Castle. But there were tensions. Philip thought Helen Lightbody mollycoddled sensitive Charles and was too firm with wilful Anne.
Charles later remembered it as a ‘to-do’. Helen departed and her understudy took over.
‘Mrs’ Anderson as she was always known, even though she was unmarried and remained so, became the most important figure in Charles’s life.
The King arrives at St Mary Magdalene, the parish church at Sandringham, Norfolk for a Sunday service on March 1
She presided over a regime that became more relaxed but by no means slack. ‘Firm, even strict by the standards of a later generation, and in extremis willing to administer a smacking, she was, by nature, kind and gentle, quick to comfort and encourage,’ wrote Jonathan Dimbleby in his authorised biography of Prince Charles. She was, he added, ‘a fount of warmth, common sense and stability’.
Until 1977, when Mabel left Buckingham Palace to work for Princess Anne, pregnant with her son Peter, at Gatcombe Park, there wasn’t a morning if he was at home when Charles would not breakfast in the nursery with her.
He never forgot that it was Mabel who had sent him bottles of Vosene shampoo for his dandruff at boarding school.
Nanny Anderson never took to the informality of Gatcombe and stood down two months before the princess’s daughter Zara was born.
But her royal life was far from over. She had a seat at Charles’s wedding to Diana, although the prince’s new wife flatly refused his demand to bring her back to look after baby William.
Acutely aware of the influence Mabel had over her husband, Diana feared any influence of her own over the young prince’s upbringing would be eroded by employing her.
After the Wales’s separation, however, Mabel quietly emerged to help with William and Harry, and was taken on by Andrew and Fergie following the birth of Princess Beatrice.
When she turned 80 it was Charles, naturally, who organised a party – a sit-down dinner at Clarence House where her royal life began.
For Charles she continued to provide one other valuable service: keeping his favourite teddy bear patched up. She was the only person he trusted to darn the threadbare cuddly toy that has always gone everywhere with him.