Kate and William were married in a lavish televised ceremony in 2011. Photo / Getty Images
It was teatime on the day of the royal wedding, and the Duke and Duchess of Cambridge had just wowed the crowds outside Buckingham Palace by emerging from the gates in a dark blue Aston Martin DB6 MkII featuring the number plate JU5T WED.
Waving from the stylish convertible, belonging to the Prince of Wales, as an RAF helicopter flew overhead, it brought a formal day of royal pomp and pageantry to a light-hearted end as the joyful newlyweds motored up The Mall before parking outside Clarence House, Prince William's former London home.
Unbeknown to the flag-waving well-wishers outside, there was another spontaneous moment of informality as the bride and groom, still dressed in their wedding finery, rejected the offer of a glass of the finest Champagne in favour of a pot of tea for two instead.
The touching incident appeared to characterise the normalcy of a couple who only hours earlier had been married before a global audience of millions in scenes reminiscent of Prince Charles' wedding to Lady Diana Spencer in 1981.
Yet a decade on and that is where comparisons end, with William and Kate thriving where his father and mother once faltered.
Three children later and now arguably the most pivotal post-Megxit players in the House of Windsor, the future Prince and Princess of Wales have never been under more pressure to step up in support of Queen and country.
As they mark their 10th wedding anniversary, they have just cause to reflect on what has undoubtedly been a difficult 18 months of their royal alliance in the wake of the Duke and Duchess of Sussex's departure to the US in March last year.
As well as being the most directly affected by Harry and Meghan's desire to "work towards becoming financially independent" from the Firm, they have also had to suffer the ignominy of the LA-based couple's televised outpourings to Oprah Winfrey, when Meghan accused Kate of making her cry during a bridesmaid's dress fitting and Harry described his brother as being "trapped" in the monarchy.
Although the squabbling royal siblings took the first tentative steps towards a rapprochement following the Duke of Edinburgh's funeral at Windsor Castle earlier this month, with Kate's encouragement, it is fair to say the relationship between the so-called Fab Four is far from back on an even keel.
However, as they celebrate the milestone, traditionally represented by tin to symbolise the strength and durability of a union that has stood the test of time, the Cambridges deserve to take comfort from the fact that they have found equilibrium in their own relationship.
For what started out as an uneven match between blue-blooded prince and his Bucklebury-born "plus one", and even ended in a brief but highly-publicised split in 2007, has now blossomed into a marriage of equals.
Sources close to the couple have long been at pains to point out that theirs is a two-peas-in-a-pod kind of partnership. As one royal insider put it: "They are both very similar in the respect that they are intrinsically quite shy people who have sometimes struggled with life in the limelight.
"When he is having a difficult time, she is the one who helps him through it but it works both ways. He is there for her and she is there for him." Citing the "slightly competitive edge" to their relationship, the source added: "But ultimately they are very much on the same side, on the same team. There is quite a lot of affectionate joshing between them but they have always had each other's backs."
Some may even go so far as to suggest theirs is a "seesaw" marriage, where the roles of breadwinner and childcare provider are fluid and interchangeable. Determined for one of them to always be at home to see Prince George, 7, Princess Charlotte, 5 and 3-year-old Prince Louis off to school in the morning and tuck them in at night, there is a sense that the couple take it in turns to have their moment in the sun as well as putting on a united front when required.
As evidenced by the mutual giggling over their golf skills during a visit to Durham on Tuesday, they are arguably better together, notwithstanding the fact that William has made considerable headway as a diplomat and statesman with solo visits to China, Jordan, Israel and Palestine while Kate has also carved out a niche as an expert on early years learning as well as branching off into individual projects, such as designing a garden for the RHS Chelsea Flower Show in 2019.
According to Katie Nicholl, author of The Making Of A Royal Romance, about William and Kate's love affair: "When they are planning their diaries, like when William went to Israel, it literally came down to looking at timing of flights to ensure that he could still be there to see the children before he left.
"When they do go away together, they have got Kate's parents, Michael and Carole Middleton, to fall back on as well as their long standing nanny, Maria. They have a really strong support network that they absolutely trust."
Agreeing theirs is very much a "seesaw" marriage, Nicholl says: "I think there has been a bit of a role change in this relationship in the last year. Kate's very much been the pillar of strength, guide and mentor for William that he has always been for her.
"He's had a really hard time with his brother, he's really struggled with it and she's been a rock. When he was ill with Covid, she was the one nursing him and pulling it together and putting on a united front. She's really shown the mettle – and he loves that about her – and as such, he's let her take the lead."
A palace insider agrees, but adds: "The opposite is also completely true. A lot of her growing confidence is down to him. She has never tried to be the front man and has always seen herself more in a supporting role, but he's tried to push her out of that at points because he knows what she can achieve."
Citing the keynote speech Kate made in November to reveal the key findings from a 57-page Royal Foundation report on early childhood, Nicholl adds: "That speech showed how full circle Kate has come. William has faith in her but so has the family. When he needs to be in the background, she rises to the occasion, and vice versa."
In the first three years of their marriage, when they were based on Anglesey, where William was working as an RAF search and rescue pilot, the newlyweds were criticised for shying away from fulltime Royal duties, at one point even cruelly dubbed the "can't-do-won't-do-Cambridges". But as with their eight-year courtship and gradual ascent to top flight public service, the couple whose destiny has always been mapped out before them have treated their royal lives as a marathon rather than a sprint.
Nicholl recalls: "I remember covering their first mini tour of the UK immediately after they married and Kate was really nervous. She was still learning the ropes. If you compare that to her confident composure at the Duke of Edinburgh's funeral then you realise what a class act she has become.
"Watching them over the past decade, they are the couple who finish each other's sentences. As with any marriage, there have been ups and downs, but they have got through them. This is a marriage based on friendship. That long courtship has stood them in good stead. William took his time to marry Kate because he wanted to be sure it would last forever. Three is the number of children they are going to have – they won't have any more so they are now at a turning point in their lives and stronger than they ever have been."
Kate turns 40 next January, with William following suit six months later – a milestone in anyone's life but arguably an even more significant staging post after everything that has happened since Harry and Meghan dropped their Megxit bombshell in January 2020.
Having matured and mellowed as parents, the onus is now on William and Kate to be the grown-ups of their generation, echoing the Queen's personal sacrifice in the name of public duty.
As the Duke made clear in his tribute to his beloved grandfather – the couple stand ready to play their part. "I know he would want us to get on with the job," William said.
A decade in, but still so much work to do.
The average age of patients in the study was just 38, highlighting risks for younger adults.