Sam Hallam walked free, escaping a fate almost worse than death | Erwin James

Seeing the pictures of Sam Hallam enjoying his first steps of freedom after being cleared of the 2004 murder of Essayas Kassahun brought back vivid recollections from my own prison experience. Hallam served seven years before evidence emerged proving beyond doubt that he was innocent. But I can imagine how it must have been for him as he trod the landings, first of all at Feltham young offender institution and later in the adult prison system. His case would have been at the forefront of his thoughts, from his waking moment to the seconds before sleep. I doubt he ever slept well.

For the seven years he served, the core subject of the majority of his conversations, with fellow prisoners, with staff, with friends and loved ones on visits and in letters would have been his innocence. His supporters – and Hallam had many, including the actor Ray Winstone – would have believed him. But on the landings, on the yard and in the workshops it would have been different. During risk assessments by a multitude of prison professionals, all his protestations and rationalisations would have been interpreted as "cognitive distortions". His file would have been stamped, IDOM. In Denial of Murder. As an IDOM, his risk level would have been deemed too high to allow him to progress through the system. If he hadn't been cleared, his prison future would have looked bleaker than the genuinely guilty.

His sentence had a beginning, but no middle and no end.

I remember living with innocent people. You don't know it at the time, though sometimes there are clues. In one high security prison I lived alongside a number of IRA prisoners, one of whom was the highest-ranking IRA officer in British custody at the time. The same prison held three of the Birmingham Six. I saw how uneasy the IRA men became whenever they encountered any of the three, in the gym or on the yard. It was obvious to any observer that the Birmingham men had no connection with the bombers.

In other cases the truth is not so obvious. If someone in a neighbouring cell wants to proclaim his innocence, well that's his business. Inside it's every man for himself. Who is anyone in there to judge anyway? But when someone you've served alongside for years is eventually cleared, the impact is shattering.

George Long was such a man. Good old George, always had a smile and an offer of help whenever it was needed. When the prison chaplain decided to stage a musical for local elderly people in the chapel, George, skilled with arts and crafts, begged, borrowed and, ahem, stole, the raw materials to make the costumes. He worked so hard, often through the night to get everything ready for the show. He said to me once: "I might not supposed to be in here, but while I am I'm going to do some good." Fifteen years on, George got his shout at the court of appeal and his conviction for murder was quashed. John Roberts was another. In his early 20s he too was convicted of murder. I used to sit next to him in the braille transcription workshop. Every day he told me and others he was innocent. "My mum knows I didn't do it," he'd say, "She'll never give up on me." Sure enough and again after 15 years I opened a newspaper one day to see a picture of John on the steps of the appeal court after his conviction was quashed – with his mother at his side.

"Thank goodness for mothers," I remember thinking.

When Stephen Downing walked free after 27 years in prison for a murder he did not commit, I was the last prisoner he spoke to. I worked in the prison reception area. The discomfort of the prison officers who had to administer his release was palpable. Stephen, who had been convicted aged 15 was naturally buoyant. Some months earlier he'd shown me a report from the prison psychologist describing him as "highly dangerous". We shook hands and I wished him good luck just before the big gate slid open and out he strolled. As I watched him go I remember my heart pounding probably almost as hard as his.

Like anyone should be, I'm glad for Sam Hallam. Murder victims should never be forgotten. But like George, John, Stephen and countless others over the years Sam too was served badly by the justice system and turned into a victim. Being sentenced to life imprisonment is only, to my mind, marginally better than being sentenced to death.

For many lifers a death sentence is what it becomes. Sam's release is good news, but we mustn't forget there will be others in there who may never get their shout.

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