This was Gerry Conlon's moment. There he is, jumping for freedom, an innocent man who'd served 15 years for the Guildford Four pub bombings. Today he is a broken man. And the system that broke him has done little to put him back together again. That has been left to a network of the falsely convicted, whose members know to their cost the real price of freedom

It is one of the enduring images of the 20th century. Gerry Conlon, with his sisters Anne and Bridie clinging joyfully to him, emerges from the Old Bailey, handsome, smiling and punching the air as he is freed after 15 years of wrongful imprisonment.

For Conlon and the rest of the men who had been convicted of two pub bombings in Guildford in 1974, the past had been defined by corrupt police officers, complicit forensic scientists and gullible courts. They had endured terrible beatings, isolation and despair. But on that day in October 1989, the future finally looked bright.

Fast forward 11 years. Conlon is alone in a small flat on the south coast of England. His voice on the phone is desperate.

"I can see them, the men I saw die in prison," he says. "There was one who got some glue and cut up his mattress and glued the bits to his body and then set himself alight. I can still smell the burning flesh. I can't get it out of my mind."

There are lots of things Gerry Conlon can't get out of his mind. There is the sight of his father, Giuseppe, also wrongly branded a terrorist, wasting away in prison before his eyes. He can remember the beatings. He has nightmares about being stripped, spat and urinated upon. And the sound of boots echoing on metal, coming closer to his cell.

Conlon was 35 when he was freed on appeal. Now, after years of alcohol and drug abuse – including crack cocaine – he is in trouble. For, like all his fellow victims of miscarriages of justice – the Birmingham Six, the Bridgewater Three and others, less well-known – Conlon was thrust into a shameful vacuum, a place where people like him were forgotten by the state.

"We got no help whatsoever, no support, no counselling," he says, "but we were so terribly, terribly damaged. I still am. I never had a single thought about killing myself in prison, but now I think about nothing else. I plan it, I buy things to do it. I have a knife and some rope and lots of pills. If not them, then I have my balcony. I keep it locked for now because I dream of jumping off it. Prison was better than this."

A lot of people are concerned about Gerry Conlon, and are trying to help. But they are not officials, professionals or representatives of the state. Instead they are fellow victims of miscarriages of justice, men and women whose campaigning has switched from releasing innocent people to keeping them in one piece now that they are free.And at the heart of this network are two of the members of the Birmingham Six.

Paddy Hill and Billy Power both served 16 years after being convicted of the Birmingham pub bombings in 1974. They were released on appeal in 1991. Today, despite never having received full compensation, they repeatedly open their homes to other victims as they are freed into a world that does nothing to help them.

One of the people they have taken in is Jim Robinson, one of the Bridgewater Three (the men who were wrongfully convicted of the murder of newspaper boy Carl Bridgewater in 1979). He served 18 years before emerging with nowhere to live. Billy Power and his wife Nora gave Robinson a home for more than six months.

Meanwhile, John Kamara, 44, is just the latest in a series of guests at Paddy Hill's two-bedroom flat in Muswell Hill, north London. He was freed in March after 19 years, when his conviction for the murder of a Liverpool bookmaker was quashed (among the reasons for his release was the discovery that the prosecution had withheld 201 witness statements from the defence).

"Without Paddy's help, I'd be living rough on the streets," says Kamara. "During my appeal in March, the judges announced a 10-minute recess, then came back and quashed my conviction. That was it. After 19 years, I was given a £46.75 discharge allowance and a London Transport pass that expired at 8pm, and I was kicked out of the side-door of the court."

After Hill came to his rescue, Kamara's experiences mirrored those of all the victims.

"When I asked for income support," Kamara says, "one of the people I saw said: 'You'll be getting compensation, won't you? Go down to the bank and get a loan.' I went to the Woolwich but they turned me down. I had to give 'prison' as my previous address."

Eventually, after Hill's doctor agreed to provide temporary sick notes, Kamara found he was entitled to £52-a-week income support. There will be compensation, but the interim is a miserable place in which to live.

"You get no help at all," Hill says. "The judge quashes your conviction and you feel elated, but then you emerge with no money, no accommodation, no health care, no counselling, nothing to equip you for the place you have been away from for so long."

For the time being, Kamara will stay in Hill's home. There is an element of prison camaraderie in their existence. Kamara, a lean Liverpudlian, has the "big" room – actually a small space, cluttered with black bin-liners filled with the evidence that freed him. The boxroom is reserved for Hill's 27-year-old son Sean, for when he returns from his job as a travelling chef. There is no bed for Hill: he sleeps on the sofa.

Hill, who now runs the Miscarriages of Justice Organisation, has had a steady stream of house guests, including Patrick Nicholls, who served 23 years after being wrongfully convicted of murdering a friend. He was almost 70 when he was released two years ago.

"When Paddy Nicholls came out," Hill says, "he knew no one on the outside and had nowhere to go. He had had two strokes, and was wheeled up to me, looking completely bewildered, by a prison guard. He had a sponge ball in his hand to squeeze as part of his physiotherapy. But they even took that off him.

"We tried to get him benefits, but he needed a sick note. We tried to get him a doctor, but then he needed his medical records, which were held by the prison service. He needed medication, so I rang up his old prison to ask what it was. But they wouldn't tell me."

Gareth Peirce, the solicitor who represented both the Guildford and Birmingham defendants, has also had to step into the breach to help victims. She provided accommodation for more than six months for Gerry Conlon and Judith Ward, the latter wrongly convicted of the 1974 M62 coach bombing in which 12 people died. She served 18 years.

"They had nowhere to go and there was no provision for them from the state," Peirce says. "All of these people should have been given the same kind of help as the returning hostages, John McCarthy, Brian Keenan and Jackie Mann.

"A few years ago, Adrian Grounds, a psychiatrist at the Institute of Criminology at Cambridge, examined Gerry Conlon and four of the Birmingham Six. He found that they were suffering from irreversible and disabling post-traumatic stress syndrome, and said that their mental condition was similar to people whose brains had been damaged in car accidents."

For nine years, Sally Mulready, a benefits adviser at the London-Irish Centre in Camden, north London, has been fighting the benefits and pensions systems, wrangling with housing officers to try to help the stream of miscarriage victims who emerge from prison.

"Paddy Nicholls was particularly bad," she says. "I spent days with him during which he would just cry. But they are all damaged in their own way. These people had dreams – but when they came out, life didn't live up to their expectations.

"There needs to be a more rounded approach from the Government. From day one, these people need proper care, and that's going to cost money."

This week, the Government made one small step when it announced that it would plug an appalling gap in provision for miscarriage victims. It agreed to make up absent National Insurance contributions after the Birmingham Six, some of whom are coming up to pensionable age, found that they were not entitled to a state pension because they had paid no "stamp" for 16 years – while they were wrongly imprisoned.

Victims are often deprived of sympathy because of the assumption that they must be fabulously wealthy. "People sometimes argue, 'Well, they get lots of compensation', but they don't," says Peirce. "Once you deduct lost and projected earnings, the compensation element of being wrongly locked up, beaten and abused for years, averages out at about £13,000 a year."

The Birmingham Six have each received interim payments of up to £300,000 – but they are arguing for more. This may seem a lot of money, but it includes nine years' living expenses, and the purchase of a home. And as they will be the first to admit, they all spent money trying to buy the love of their children and their grandchildren.

"I was typical," Paddy Hill says. "I hadn't seen my kids out of prison for 16 years, so I tried to build up a relationship by buying things for everybody. What do you do when your grandchildren run away from you because they're scared? You try to buy their love."

And compensation alone is not the answer. Michael Hickey was just 17 when he was convicted, with Vincent Hickey and James Robinson, of the Carl Bridgewater murder. When he came out 18 years later, he needed therapy more than cash – but he was told to join a long NHS queue.

"He was clearly a damaged and broken person," his mother, Ann Whelan, now says. "He wasn't equipped to deal with the world, and I wasn't equipped to deal with him. He was given no professional support at all. The pressures were massive and they proved too much for him."

Over a six-month period, Michael withdrew into himself, not knowing how to deal with his new world. "We tried to teach him, but it was difficult – he had never seen a microwave oven, a TV remote control or a mobile phone," Ann says.

He would refuse to sleep in a double room, preferring a cell-like box-room. His stomach could not cope with rich, non-prison food. He would curl up and cover his head at the slightest noise. "He would draw the curtains and stay in all day, crying," Ann recalls. "I would get phone calls from people saying they had seen him in the middle of the night simply sitting at the side of the road somewhere, looking into space.

"When he got some interim compensation, he either just gave it away or people took it from him. He didn't care. He would pace around the garden, talking to himself about things that happened in prison.

"And, finally, one day he snapped. He was standing in the garden, shoeless and in his shorts. He began screaming, and threw his watch in the pond and a chair across the lawn. I was terrified – I rang his solicitor to ask for advice and was told to call the police.

"In my panic, I did. When they arrived, they were in riot gear carrying shields. Michael just went quiet and looked at me. And then they took him away. They sent him to a psychiatric clinic near Birmingham. Every time he breaks down, he goes back there for emergency medication. It's happened about 10 times now.

"I broke my heart that day. I thought that after 18-and-a-half years' campaigning to get Michael out, I had been responsible for him being incarcerated again, and I should never, ever have been placed in that situation."

Meanwhile, Gerry Conlon lives alone, fighting his past and his various addictions, never socialising, and angry that he believes he will never form a relationship, never have a child.

But his pain, and that of the others, past and future, could be allieviated if the state would only face up to its responsibilities and give the help they need. There must surely be something wrong when a man says, as Conlon did this week: "I was better off in prison."

Additional research: Morgen Weaver