As the government’s director of communications, Alastair Campbell held a position in one of the most pressurised environments imaginable.

Dictating the public relations of Downing Street during Tony Blair’s New Labour, Campbell developed a reputation as a ruthless, no-nonsense operator, and he admitted he gained strength in that role after overcoming his previous struggles with mental illness.

In 1986, as a journalist working in Fleet Street, Campbell suffered a breakdown after battling alcoholism and spent time in hospital.

Since then, he has spoken frequently about his struggle to bounce back from the lowest point in his life, which he describes as a worse experience than losing a loved one.

And Campbell has urged employers to create an atmosphere of appreciation and acceptance to remove stigma attached to mental health, citing one phone call from a former editor as a seminal moment in his fight back.

“It was one of those moments that was life changing because I had left him on the Mirror – he was really angry with me, felt I was doing the wrong thing for him and for me,” said Campbell.

“But he was one of the first people who phoned me to say ‘come back when you’re fit’ and that was a massive weight off my shoulders and I’ve never forgotten that.

“What was amazing was we became very close friends – he not only ended being my editor again but also he edited my diaries.

“I feel I owe my breakdown a lot – my sister recently said she saw me talk about it on the television, and asked me why I didn’t just let it go.

“But I don’t want to really, because I hold it there as a yardstick that for me - it was even worse than that because I actually thought I was going to die.

“It was completely irrational but that’s what I thought.”

Campbell was speaking at a forum for Not a Red Card, a campaign by financial services company Legal & General aimed at using sport as a means of tackling the stigma surrounding mental health.

And Campbell, an ardent sport-lover and lifelong Burnley supporter, believes sport can be a catalyst for people in everyday life to take the first step on the road to recovery.

“Sport is such a big part of our national culture,” added Campbell, who is an ambassador for mental health charity Time To Change.

“We identify even more now with celebrities or well-known people – leading sportspeople have got a real hold on people’s imagination and culture.

“When more high-profile people talk about their struggles, it’s empowering for people. One man told me he was experiencing a breakdown at the same time I was talking about mine on the television, and it gave him something to hang on to.

“The more we talk about this, the more we actually do help each other.”

The summit, held at Twickenham Stadium on Thursday, saw athletes including 11-time Paralympic champion Tanni Grey-Thompson, London 2012 and Olympic gold medal-winning hockey star Helen Richardson-Walsh, join discussion panels with business people to share their experiences in dealing with mental health problems.

Keynote speeches, including from Campbell, also took place at the Home of Rugby.

Nigel Wilson, CEO of Legal and General, said: “We think of it as an iceberg – a little bit of it is visible to us but there’s a huge amount below. As a society, we’ve got to raise it up and melt it.

“It’s the most difficult part of my job dealing with mental health issues across the group because there’s so few solutions.

“It is just so difficult to come up with the right solutions in the mental health area and it’s a growing problem everywhere.

“Today was remarkable for its honesty, integrity, the openness people had, the active engagement there was from the participants all the way through and it’s not a one-off event – it’s the start of a journey.”

Find out more at www.legalandgeneral.com/notaredcard or by searching #notaredcard