Turning 40 is a milestone moment for anyone, but for Prince William, it is particularly important. As he enters a new decade, William knows that he will likely become the next Prince of Wales in his 40s. His wife, Kate, Duchess of Cambridge, will become the first Princess of Wales since his late mother, Diana. With an aging monarch—his grandmother the Queen is 96, and an heir apparent in his 70s (his father Prince Charles turns 74 in November) William is not only inching closer to the throne, the future of the monarchy rests heavily on his shoulders.

The prominence of the Cambridges at the recent Platinum Jubilee celebrations was both telling and deliberate. While Charles and Camilla, Duchess of Cornwall—who were central to the celebrations, supporting and standing in for Her Majesty—will be the next King and Queen of the United Kingdom, the long-term future of the House of Windsor lies with William and the Cambridge dynasty.

It is a prospect that once weighed heavily on Prince William. When he was a gap year student, he traveled to Chile where, according to someone he was with, he was painfully aware of the burden of his birthright. “We were all sitting round a campfire excitedly discussing our futures,” the friend I spoke with explained. “William said ‘you’re all so lucky. I’ll have to be king one day.’ It seemed like a lot for him to bear.”

Now, that moment is not so far in the future and while there is no chance that William will “leapfrog” his father the Prince of Wales, who will succeed Queen Elizabeth, William is preparing for his future reign by laying down the foundations now. His promise to tackle the issue of homelessness, a cause inspired by his mother’s work and very much at the heart of this milestone birthday, is a good indicator of the type of king he will one day be. He wants to smash stigmas and make a difference where he can.

As one person who met William while he was recently selling Big Issue magazine remarked, he is “the people’s prince.” Those who know him believe he will be a modern-day monarch, who wants the Royal Family to be relevant and meaningful to everyday people in a fast-changing world. 

In the past, William has admitted to not giving the idea of being king much thought. But recent events, including his brother Prince Harry’s decision to stand down as a working royal, the turmoil caused by the COVID pandemic and the Queen’s ill spate of health have had a direct impact on William. He has had to step up to the plate. And in doing so, he has proved to be a solid and dependable statesman. 

In 2017, he gave up his career as an air ambulance helicopter pilot. It was a position he loved, but the job that really mattered was calling. At the time Prince Philip, the late Duke of Edinburgh had just retired and although the Queen was carrying out around 300 engagements a year, and Charles more than double that, there was a growing pressure on William to take on full-time royal duties. “There was talk at the palace that the duke needed to make up his mind whether he wanted to be a pilot or a prince. I think there was a sense of frustration that he was not doing more official engagements,” says one palace insider. 

William, who can be stubborn, had refused to be pressured into taking on full time royal duties until this point. It was important to him that he and Kate, and their young family were able to enjoy an “ordinary” family life and he loved having a civilian job that had a real impact on people’s lives. 

In retrospect, he was wise not to succumb to pressure to be hurried into full-time royal duties. The opportunity to have a meaningful career and enjoy the early years of his children's lives in relative peace and privacy (something his father never had) has meant that William is all the happier today. The Queen supported William’s decision, having herself enjoyed several years in Malta with Prince Philip as a naval officer’s wife. Now, however, she needs and depends on William more than ever as the royal family goes through a fundamental transition.  

While the Queen has no plans to abdicate or retire and will continue to serve, her statement at the close of the Jubilee celebrations made it clear that she needs the support of her family. Since suffering from mobility issues, Her Majesty has scaled back her public engagements and is handing more responsibilities to Prince Charles and Prince William.

Their roles as her chief substitutes have become increasingly apparent in recent years, with Charles and William carrying out the lion’s share of overseas tours on behalf of the Queen as well as investitures and increasingly state occasions. During the COVID-19 pandemic, William and Catherine stepped up as front-line royals to support the Prince of Wales and the Duchess of Cornwall as the Queen sheltered at Windsor Castle. And it is expected more duties will fall to William as Charles carries out more on behalf of his mother.

Last month, the Prince of Wales undertook the State Opening of Parliament for the very first time with William by his side. It was another powerful image of the future as well as a valuable opportunity for William to witness up close the speech he will one day deliver. 

But perhaps the greatest indicator of William’s increasing responsibilities was his role at the recent Platinum Jubilee. William was by his father’s side when Charles took the royal salute at Trooping the Colour, and in the Queen’s absence, the focus was very much on her successors.

While neither Charles nor William want to think about the Queen’s demise, the death of Prince Philip in April 2021 has in the words of one former courtier “sharpened the focus on the future.” According to the source, this is something Charles and William speak about on a regular basis.

“They are absolutely on the same page, in fact they are closer now than they have ever been,” says a family friend. “They speak almost every day and they have a very loving and genuine connection. They believe in the monarchy, that it has a genuine purpose and that it has a future. They recognize that it has to modernize and that there will be changes in the future when the Queen’s reign comes to a close.”

Father and son agree the monarchy should be scaled down with fewer working royals and they are both adamant that Prince Andrew can have no place in public life. It was reported that William threatened to pull out of last week’s Order of the Garter Service if Andrew was allowed to join the procession and one source told me that this is typical of an increasingly focused and outspoken Duke of Cambridge. 

“He’s much more confident in his role and the position he wants to have,” remarks a former aide. “We saw that with Andrew but also on the Caribbean tour and how he came out and said he was open to changes within the Commonwealth at the end of it. This was his view, it was a sign of what we might see in the future and a new confidence.”

William and Kate’s tricky tour of the Caribbean was marred by some controversial photo opportunities such as the time they visited a football club and were seen shaking hands with Black fans through a metal fence. Their tour of a military ground in an open-top Land Rover was also criticized. William and Kate had been wary about the optics but hadn’t wanted to offend their hosts in Jamaica so they went along with the engagement and in doing so faced a fierce backlash. Rather than just take the criticism William spoke up and issued a powerful statement at the close of the tour in which he said:

“Foreign tours are an opportunity to reflect. You learn so much. What is on the minds of Prime Ministers. The hopes and ambitions of school children. The day-to-day challenges faced by families and communities. I know that this tour has brought into even sharper focus questions about the past and the future. In Belize, Jamaica and The Bahamas, that future is for the people to decide upon. But we have thoroughly enjoyed spending time with communities in all three countries, understanding more about the issues that matter most to them. Catherine and I are committed to service. For us that’s not telling people what to do. It is about serving and supporting them in whatever way they think best, by using the platform we are lucky to have.”

It was an insight into how he sees the monarchy and the Commonwealth changing. He doesn’t want to force anything onto anyone. “I don’t think he’ll be a political king, but I think he will speak up on the issues that matter to him,” says a former aide. 

As he turns 40, we are seeing and hearing more from William and his telegenic young family. While there was a time the prince could be shy in front of the camera, and kept his children out of the limelight, William has mastered the art of the TV interview and public speaking. He is more comfortable with his children Prince George, Princess Charlotte and Prince Louis taking a place in the spotlight, but not too often and not for too long. 

Those who know the Cambridges best say that it is William’s happy home life and his ten-year marriage which have made him the duke he is today. Kate is the backbone of it all, and having finally found a happy balance between his public personal and his private life William at 40 is truly content. 

Of course, there is still his ongoing rift with his estranged brother Harry. There wasn’t a reunion at the recent Jubilee, however, sources close to the princes are hopeful they will one day smooth things over. “My sense would be that it is something that plays on his mind a lot,” says a friend. “The thing is, William knows they are stronger when they have each other in their lives. In time I’m confident that can happen. The hope is one day it will be resolved.”

For now William is focused on putting the framework in place to make sure the next decade is as successful as the last. The speech he delivered about environmentalism during the Platinum Jubilee celebrations is the kind of speech we can expect to hear more of. Having launched the Earthshot Prize, to find ways to help protect the planet, William is committed to making this his raison d’etre. 

“That speech was very telling,” says the former palace aide. “His father gave a brilliant speech about the Queen, so instead of trying to emulate that, the Duke gave a speech urging people to do something about the planet. It was his way of speaking to the young generation, from a very authentic place. It’s where he believes he can make a difference.” 

“William and his team are plotting out the next ten years,” says another source. “That’s what is on the long-term agenda at Kensington Palace. William will focus on the environment and homelessness, these are the big issues he wants to push. Selling the Big Issue wasn’t a flash in the pan or a photo opportunity, it is the first stage in a big new initiative. It will be Royal Foundation led and a collaborative model which we’ve seen in the past.” 

And expect to see the Duke appeal more to the next generation. They will after all be his future subjects one day. 

“Nothing can be done if you don’t have the young generation on board and he knows that,”  adds the source.  

William knows that the monarchy has to modernize in order to survive. He plans to continue his grandmother’s legacy, when it is his time on the throne, just in his own way.