Social media can be a hard habit to break, caring Kate tells students

“It’s hard to break away from,” she told a girl who said she had struggled with the pressures of maintaining a presence on services like Facebook and Twitter.

“It becomes part of your lifestyle, doesn’t it?” the Duchess said.

“It’s great in so many contexts, but it’s also being able to monitor your own use of it as well, which is great,” she added.

Kate, who is pregnant with her third child, met pupils and parents who had been supported by the mental health charity Place2Be, as she toured the Reach Academy in west London.

The charity, of which she has been a royal patron since 2013, helps children deal with bullying, bereavement, domestic violence, family breakdown, neglect and other issues.

Ed Vainker, principal of Reach Academy, said he believed that teachers must work closely with families if children were to get the most out of school.

He said: “We got the 15th best GCSE results in England this year, and I think there’s a narrative that schools are either great for academics or they’re really holistic and support children’s well-being.

“We believe those two things can completely go together.”

As Kate toured the Academy, her husband was following in the steps of his mother by watching operations at the Royal Marsden Hospital.

William, who is president of the local NHS Foundation Trust, saw two robotic procedures on cancer patients.

Robotic surgery is less invasive and leaves fewer scars than open operations.

William’s mother, Princess Diana, was a patron of the Trust and famously wore operating theatre garb to watch surgeons at work at the Marsden.