He eventually stopped on the bridal shop roof and a 100-strong crowd gathered in the street below.
Timothy Braithwaite, who witnessed the scene, said he was horrified at the ghoulish behaviour of those taking videos. "There was a woman with kids filming it - I don't understand how you can be there with kids in the first place, never mind filming it. It's disgusting," he said.
The injured man's parents, who said the incident was "completely out of character" for their son, condemned the actions of those involved.
In a statement, they said: "He is a vulnerable man who has had to deal with some significant challenges in his life and when he clearly needed compassion and understanding was met with cruel taunts and encouragement to end his life.
"Despite this, he is hanging on in hospital and we are hoping he will recover. If he does, he will have a long journey ahead of him."
A woman in a nearby office described hearing people encouraging the man to kill himself.
"There were some people shouting at the man to jump - one man who shouted was angry because he couldn't get to the Job Centre as it was within the cordoned off area," she said.
"I also saw three people filming what was going on and others were taking photographs too. Taking a video is definitely crossing the line. And it's even worse that they then posted the videos on the internet - I just don't understand it."
The woman also described the moment the man, who is from Portsmouth, jumped off the roof.
"Everyone in the street gasped when he jumped. The sound was horrendous; it was a combination of a loud thump, a crumple and a bang.
"As we are on the second floor of the building I actually saw him fly past our window while I was looking out."
Matt Dennison, 22, a trainee manager at Games Workshop, another shop within the cordoned off area, said it was 'sick' that people took videos of the incident. He said: "There were easily 100 people gathered there and some were shouting 'Jump' at him, which I thought was horrible.
"It's not acceptable, I wasn't sure if I even wanted to stay and watch what happened so I went to get a coffee.
"I wasn't there when he actually jumped, but I heard that lots of people screamed when it happened.
"But people filming it all, just to get a few hits on YouTube, are sick - I don't see the point.
"It's the man's decision to end his own life and people shouldn't have taken advantage of the situation."
Hampshire Constabulary said it had contacted the internet sites which had posted the images and asked for the footage to be removed.
A spokesman added: "This was a disgusting display by members of the public. It was undignified and callous.
"It showed a complete lack of empathy for the person involved and for officers trying to deal with a very sensitive situation under immense pressure.
"This was a very unpleasant event which could have been traumatic for those who witnessed it."
The man was at Southampton General Hospital with his family at his side.
- Daily Mail
