Catherine, Princess of Wales has warned screentime is causing an "epidemic of disconnection"

In an essay written in collaboration with Professor Robert Waldinger from Harvard Medical School for her early years education campaign, she said: "While digital devices promise to keep us connected, they frequently do the opposite."

The princess noted in the essay, which has been published on the website of the Royal Foundation Centre for Early Childhood, gadgets have become a "constant distraction, fragmenting our focus" and undermining the time that families spend together.

She wrote: "We're physically present but mentally absent, unable to fully engage with the people right in front of us."

The essay explains research shows the importance of creating healthy and warm relationships within families and between people for the sake of both physical and mental health, but warned that social trends are going in a different direction, leading to more isolated and lonely people, a particular challenge for children growing up in a "world immersed in digital technology.

Catherine wrote: "When we check our phones during conversations, scroll through social media during family dinners, or respond to e-mails while playing with our children, we're not just being distracted, we are withdrawing the basic form of love that human connection requires."

The princess - who has three children with husband Prince William - expressed her belief that children need encouragement to develop social and emotional skills but that can be impeded by a "world filled with technological distractions".

She wrote: "We're raising a generation that may be more 'connected' than any in history while simultaneously being more isolated, more lonely, and less equipped to form the warm, meaningful relationships that research tells us are the foundation of a healthy life."

William recently revealed he and Catherine are "very strict" about not letting their children, Prince George, 12, Princess Charlotte, 10, and Prince Louis, seven, have mobile phones.

Discussing if they have dinner together, he told Eugene Levy on his Apple TV+ series The Reluctant Traveler: "Yep, absolutely, yep definitely. So, we sit and chat; it's really important. None of our children have any phones, which we're very strict about."