Britain's Prince Harry has said he used alcohol and drugs to cope with the trauma of the loss of his mother, Princess Diana.

The British royal was just 12 when Princess Diana died in a Paris car crash in 1997 while being pursued by the press.

In the first three episodes of his mental health series with Oprah Winfrey, titled The Me You Can't See, the Duke of Sussex addressed some of his traumatic childhood memories, including the moment he was famously photographed with his brother, father, uncle and grandfather walking behind Diana's coffin at her funeral.

He told co-host Winfrey: "For me the thing I remember the most was the sound of the horses' hooves going along the Mall.

"It was like I was outside of my body and just walking along doing what was expected of me. (I was) showing one tenth of the emotion that everybody else was showing: This was my mum – you never even met her."

He said the trauma of Diana's death caused him to suffer anxiety and severe panic attacks from ages 28 to 32.

"I was just all over the place mentally," he said.

"Every time I put a suit on and tie on … having to do the role, and go, 'right, game face', look in the mirror and say, 'let’s go’. Before I even left the house I was pouring with sweat. I was in fight or flight mode."

He said: "I was willing to drink, I was willing to take drugs, I was willing to try and do the things that made me feel less like I was feeling."

He told Winfrey he would drink a week's worth of alcohol on a Friday or Saturday night "not because I was enjoying it but because I was trying to mask something".

During the programme the duke also accused the royal family of "total neglect" when his wife Meghan was feeling suicidal amid harassment on social media.

Harry said he was ashamed the situation had got "that bad" and also suspected the royals would not have been able to help.

Pop superstar Lady Gaga and actress Glenn Close also featured in the documentaries, with Gaga discussing her serious mental health struggles after she was raped as a teenager.