Prince William has a stark warning about the stigma surrounding mental health

Prince William has spoken out about his desire to "normalise" the "great taboo" of mental health in a powerful speech.

At the Guild of Health Writers conference at Chandos House, London, on Monday the Duke of Cambridge said it was vital that mental health should be viewed in the same way as physical health and that the subject should be normalised.

He said that until recently, people with anxiety were considered to be "weak," and those who were struggling to cope were deemed to be "failing."

"Successful, strong people don't suffer like that, do they.  But of course – we all do. It's just that few of us speak about it," said the Duke of Cambridge.

Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge attend Guild of Health Writers Conference with Heads Together at Chandos House. Credit: Getty Images

He said that his interest in mental health began with his work as an Air Ambulance pilot. "It was suicide, a subject that is so often hidden. The suicide rate among young men in this country is an appalling stain on our society," said the prince. "Suicide is the biggest killer of men under 40 in this country. Not cancer, not knife crime, not road deaths – suicide," he continued. The prince said if any one of the aforementioned issues caused so many deaths, there would be a "national outcry." "But there has only ever been silence. And this has to stop. This silence is killing good people," the prince said. The prince said that in his work as in Search and Rescue and as an Air Ambulance pilot, he has been encouraged -- along with his colleagues -- to admit when they feel "overwhelmed or unable to cope". "This should be the norm," he said.