The Duke of Cambridge has said the support of his air ambulance colleagues helped stop him sliding down a “slippery slope” towards mental health problems.

Speaking during a World Economic Forum discussion on mental health, William said one event he dealt with as an air ambulance pilot left him with “issues” and needing to speak about what he had experienced.

He did not go into details saying: “I still find it very difficult to talk about it, I get very emotional about it because it relates very closely to my children.”

During the debate he revealed not one celebrity wanted to get involved with his Heads Together mental health campaign before it started because of its subject matter.

And looking ahead to future work on mental health, he said he wanted to tackle the issue of male suicide.

The duke, who flew for two years with the East Anglian Air Ambulance, said during the discussion in Davos, Switzerland: “I was dealing with a lot of trauma on a day in day out basis, stuff that your body’s not programmed to deal with, there’s just no way it is.”

He added: “Something in the day comes along that is closely related to your own personal life and that really takes you over a line.

“It’s only natural your human, if you don’t feel anything then you need to get checked out for that.”

Duke of Cambridge
William flew for the East Anglian Air Ambulance (Heathcliff O’Malley/The Daily Telegraph)

William said: “We talked about it with my colleagues, and other guys and girls there and as a team you draw it out and you debrief about it, and the whole team was affected by this one particular job, and you manage it that way.

“I know if I hadn’t taken the action that I did then, I would have definitely gone down the slippery slope and I would have been dealing with mental illness on a different level.”

William also said past generations had dealt with the devastating impact of war by not talking about it and inadvertently passed on, what has become a British trait, of not expressing emotion.

The duke described how he struggled to recruit famous faces to support his Heads Together mental health initiative, aimed at breaking down the stigma around the issue.

The Queen and Duke of Edinburgh with the Duke of Cambridge
The Queen and Duke of Edinburgh visited Cambridge Airport to mark the opening of the East Anglian Air Ambulance’s new base (Niklas Halle’n/PA)

He said: “And what was very interesting from when we set up the campaign was not one celebrity wanted to join us, not one person wanted to be involved in the mental health campaign Heads Together.”

The duke went on to say: “Then obviously once we started getting the ball rolling, and once we started showing people a lot more what we were going to do, people realised Catherine, Harry and I put our necks on the line here, that actually maybe it was OK, we could join.”

New Zealand prime minister Jacinda Ardern praised William for his openness, saying it had helped to break the stigma and change cultural attitudes.

The second-in-line to the throne concluded his contribution by saying he was going to use sport as a vehicle to “smash” more stigma around mental health, and would work on the issue of suicide particularly male suicide.