Boxing legend Frank Bruno is back in hospital after suffering a relapse for bipolar disorder.

Just days ago the former world heavyweight champion was pictured finishing the Great North Run despite an ongoing struggle with the condition.

He voluntarily admitted himself into a hospital which specialises in bipolar disorder after his friends and family grew concerned about him.

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Just days ago the former world heavyweight champion was pictured finishing the Great North Run, pictured, despite an ongoing struggle with the condition

57,000 people registered to take part in the event from Newcastle to South Shields. Pictured is Frank Bruno at the finish line on Sunday

'It's terribly sad but Frank has been struggling for the last few weeks now and needed to get some help,' one friend said, according to the Daily Mirror's Nick Owen.

'He has taken this step in a bid to try to make sure he gets better and back to his best soon.

'Frank's a fighter and this is a battle he is determined to win.

He was due to speak about his impressive career at a dinner in Lincoln tonight but was forced to pull out because of his illness.

His manager David Davies told the MailOnline: 'After a very busy period Frank decided to seek medical assistance to help with a severe bout of depression.

The 53-year-old has been sectioned three times in the past 12 years.

Bruno's career ended abruptly in 1996 after he was beaten by Mike Tyson and risked going blind if he fought again.

He was diagnosed with bipolar disorder in 2003.

He spent two enforced spells in a psychiatric hospital in 2012 to stabilise his condition when his mental health suddenly deteriorated again — nine years after he was first sectioned.

Mr Bruno has previously described his battle with mental illness as 'the toughest fight of my life.'

Frank Bruno is reportedly back in hospital after suffering a relapse for bipolar disorder

The father-of-four last year made an emotional plea last year for better mental health treatment at the Liberal Democrat conference in Glasgow.

In the film, introducing Lib Dem health minister Norman Lamb, Bruno said: 'My name is Frank Bruno and I'm talking from experience of being sectioned about three times, two times in the last 18 months.

'I'm just a nobody really, I'm just a human being. Yesterday I used to do boxing and I used to be a celebrity, but I'm talking to you as a human being from experience.

'I met Norman Lamb and he's changed a lot of different things for mental health people.

'He's very concerned ... very, very passionate.'

ONE IN EVERY 100 ADULTS WILL BE DIAGNOSED WITH BIPOLAR DISORDER AT SOME POINT IN THEIR LIFE Bipolar disorder, formerly known as manic depression, is a condition that affects your moods, which can swing from one extreme to another. Figures show that one in every 100 adults will be diagnosed with the condition at some point in their life. It can occur at any age, although usually develops between 18 and 24. Sufferers have periods of depression, when the feel very low, and episodes of mania, when they are high and overactive. The symptoms can last for several weeks and the high and low phases are often so extreme that they interfere with everyday life. Treatment is available for the disorder and include medication, psychological treatment, and lifestyle changes. The exact causes of bipolar are largely unknown. However, it is thought that extreme stress, overwhelming problems and life changing events could contribute, as well as genetic and chemical factors. Source: NHS Advertisement

Mr Lamb hailed Bruno's bravery in opening up about his mental health problems.

He said: 'He came to talk to me about his experience ... the acute embarrassment and humiliation of three police cars arriving at your house, as if a dreadful crime had been committed. But he was ill.'

'I met Norman Lamb and he's changed a lot of different things for mental health people.'

In an earlier interview with the Daily Mail, he said: 'I don't look for sympathy, I know what I have got but I don't want people looking at me thinking I'm not right.

'But I am careful about what I do, what I say, how I act. I keep to myself. I'm not a recluse but I've always enjoyed my own company. I don't want the things I do to be taken in the wrong way'.

Bruno's career ended abruptly in 1996 after he was beaten by Mike Tyson and risked going blind if he fought again.

Mr Bruno, pictured in 1992, has previously described his battle with mental illness as 'the toughest fight of my life.'

In a television interview with Sir Trevor McDonald in 2003, he conceded was out of control and had been doing some 'very odd things'.

He blamed his severe depression on his divorce from wife Laura three years ago.

And he described the moment he realised he was about to be forcibly sectioned under the Mental Health Act.

'There was a police... two police cars, no, three police cars and two ambulancemen and I thought they were joking, taking me.

'So I was stalling and stalling and stalling.

'I didn't want to go at all. I thought this was Candid Camera coming to take me because I didn't believe I was going to go.

'And when I went there I was even giving them trouble - you know what I mean - not staying there, not defiant.

'I didn't want to leave my home at all. I couldn't believe what was happening and when I got in there after about, about a week and I realised that I needed to be in there because I was racing and fast and odd, doing some odd things.

'But it weren't funny. It weren't funny at all. It was very serious.'

Bruno, pictured at the Great North Run on Sunday, blamed his severe depression on his divorce from wife Laura two years ago

Bruno told how it was his sister who first noticed he was behaving strangely.

'She noticed that I was doing odd little things around the house,' he said, going on to describe how his condition deteriorated.

He added: 'I remember driving to Land's End and just driving in and out the lanes like a nutter, like a mad man, not disturbing nobody but just doing some strange odd, odd things.

'I was burning candles at both ends and not knowing how to relax and how to tame it down but it was a good thing that I got put in there, it was good.

'I didn't like the way it was done, with the police and the ambulance, but naturally that is a man's stupid way of things.