My friend Diana would have been such a doting granny - how cruel it was never to be, says Rosa Monckton

The birth of the Duke and Duchess of Cambridge’s first child, our future monarch, is an occasion for great joy. But in recent days I have found myself thinking how much Diana would have relished the role of grandmother.
In her all too brief time on the world stage, we saw how good she was with children: she had the ability to get into a child’s mind; her wicked sense of fun was infectious; and she could put even the most over-awed child instantly at ease.
She proved communication is not just about the spoken word — a look and a caress can be more eloquent than words.

Iconic picture of Diana as a mother: the Princess of Wales greets her sons Prince William(centre) and Prince Harry (right) on the deck of the yacht Britannia an official visit to Canada

But what people won’t be aware of is how much Diana, with her strong maternal instincts, relished the whole process of pregnancy. Indeed, she embraced any woman she saw who happened to be pregnant.
Seeing photographs of the Duchess of Cambridge shopping for baby clothes with her mother made me terribly sad that Diana wasn’t around to be part of the ritual and fun of the run-up to the birth.
I experienced how much she enjoyed this at first hand when I became pregnant at the relatively late age of 38.
I had met Diana only the month before I conceived through our mutual friend, the then Brazilian ambassador’s wife, Lucia Flecha de Lima.

The life and soul: a drenched Princess Diana with Princes Harry (centre) and William on the Loggers Leap Ride at Thorpe Park in 1997

Devoted to her boys: Diana with William (left) and Harry, joined by nanny Olga Powell in the background in Lech, Austria

When I was seven months pregnant, I was invited to Kensington Palace to have lunch with Diana. She had been following my pregnancy closely and had been full of practical advice. But the reason for this lunch invitation became clear as soon as I had sat down.
‘What shopping have you done for the baby?’ she demanded.
‘Nothing yet,’ I replied. ‘I’m busy at work.’ I was working full-time as CEO of Tiffany & Co in London.
Diana got up from the table, went to her writing desk and came back with a two-page type-written list of everything I would require — the same list she had used for her own two babies. She still had it, even though William was by then nine and Harry seven.

Another baby for Diana: the princess leaving hospital with Prince Harry, 16 September 1984 (pictured left) and posing for a formal family picture with Prince William a month later

She told me firmly that I needed to ‘get organised’. Yes, Ma’am! 
A few weeks later, Diana rang me at work and said she was going to take me in hand, as she assumed — rightly — that I still hadn’t been anywhere near a baby shop. She gave me a date and told me to bring my list.
A few days later she collected me from Tiffany’s headquarters and rushed me off to Mothercare in Kensington (since closed down, unfortunately).
Diana was a whirlwind of efficiency, sweeping items off the shelves and into our trolley — things I had never even heard of, let alone understood what they could possibly be for.

Charles and Diana with baby Prince William in Auckland, North Island, New Zealand in 1983. Diana insisted William travel with the couple abroad

The shop assistant was flustered at the till as Diana handed over her credit card. Indeed, I think it was one of the first times she had used it, rather than paying in cash, and she was rather excited about it.
As we left, struggling to walk under mounds of baby equipment, the shop door alarm went off because, in her confusion, the assistant had forgotten to remove one of the security tags.
So, we had to stagger back to the till, causing still more confusion — and stares of amazement from other mothers-to-be. It was hilarious.

Full of fun: here Diana is pictured with her sons, Harry in the middle and William on the right, in the garden of Highgrove House in Gloucestershire, 1986. William is wearing a Dallas Cowboys t-shirt

When we finally collapsed into  the  car, Diana consulted her list once more.
‘Don’t worry about a pram,’  she said. ‘You can borrow mine — and I can give you William’s  Moses basket.’
A few days later, a vast Silver Cross pram was delivered to our house, with the Moses basket inside.
Diana’s attentions didn’t end there. About three weeks before I was due, she came round to tea.
She knew I was edgy and within minutes asked me what was wrong. I promptly burst into tears and admitted I was scared: that I was the sort of woman who could run Tiffany’s, but had no idea how I would cope with having a child, let alone the ghastly (in my eyes) process of giving birth.

A protective hand: Diana carries her son, Prince Harry, off a flight at Aberdeen Airport

She calmed me down and then organised a session for me with birthing guru Betty Parsons, who had advised Diana during her pregnancies.
This terrifying but wonderful woman, then in her late 70s, arrived at my house a few days later. She taught me breathing techniques and tried to show me how to relax.
I can still hear Diana roaring with laughter when I told her how Betty had bossed around my husband, Dominic, as soon as he walked through the front door.
My first daughter, Savannah, was born just before Christmas. I was still in the delivery room when I  was told by a nurse that Diana was on the phone.
The next morning a beautiful china pot arrived full of plants, with a note saying: ‘To Rosa, just the biggest hurrah possible.’
She was round the next day to have a cuddle — with the baby, obviously.

After Prince William's birth in 1982 at Buckingham Palace: The Queen (seated left), Diana, The Queen Mother, and Prince Charles and the Duke of Edinburgh (standing)

When I brought my baby home, I visited Diana often. I used to trundle across Hyde Park, in that fug of new motherhood, pushing the Silver Cross pram to Kensington Palace. As soon as I arrived, Diana would meet me halfway down the stairs, scoop up Savannah and take over.  When my second daughter, Domenica, was born two-and-a-half years later, Diana again came to  the fore.
Domenica was very weak in the first months of her life because she had Down’s syndrome, with added complications. Diana would visit my house in Bayswater, West London, and just sit with her to give me a break.
She came with me to hospital appointments and asked questions of the medics when I was incapable of doing so. She had a tenderness that was extraordinary to witness.
Today, as I think of William and Catherine’s new baby, I remember how Diana was with my two daughters. How she would appear at bath-time, turn up at birthday parties and invite us all to lunch at Kensington Palace so she could play with them.
She encouraged Savannah to do ballet, showed her the basic moves and lay down on the floor with her to do stretches.
Diana gave her a pair of ballet shoes signed by the stars of the Kirov ballet, which, 16 years later, still hang on her bedroom wall.
We should not forget that Diana’s first job was as a nursery school teacher. It had been clear even then that she was wonderful with children and, indeed, it was the only part of her life in which she had complete confidence.
It makes it seem all the more cruel she has been denied the pleasure of being with her grandson.
This much-awaited baby will, I am sure, be the cause of national celebration. The birth of their first son will only increase worldwide interest in the Duke and Duchess of Cambridge as they move from being a couple to becoming a family.
Diana’s legacy, which until now has lain with her sons, will extend to a new generation.
Diana was made to be a mother. Her nurturing instinct was the best part of her character. She would have been the most magnificent grandmother and it makes me ineffably sad she will not be a part of the royal baby’s life.
But, of course, my feelings are as nothing to those that Prince William will experience.
One thing is certain for me, however. No matter how much Carole Middleton involves herself in the birth and early years of her first grandchild, her attentions could not be greater than those Diana would have provided.