A prisoner's life might have been saved after he hanged himself if it weren't for a "stupid" policy meaning night-shift prison officers didn't have the key to his cell, a lawyer claimed yesterday.

News of the issue emerged during a inquest into the death of mentally ill Westgate inmate Lorenzo Robinson, who was found dead on the night of July 13 2008. Mr. Robinson, a depressive schizophrenic, was incarcerated on grounds of insanity after attempting to murder a tourist. He'd made three suicide attempts inside Westgate but was not on suicide watch that night and was housed in an ordinary cell in the segregation unit.

Prison officer Melton Taylor told the inquest yesterday that only divisional officers are able to access the keys to segregation unit cells at night if there is an emergency. He explained that divisional officer Phillip Downie went to check on Mr. Robinson on the night of his death, after an alleged threat to kill Mr. Taylor.

Mr. Downie told the inquest he became concerned when he found Mr. Robinson's door blocked with paper, and he did not respond to knocks. However, he completed his checks on several other prisoners in the unit before going to get the keys to the cell from the control room at Westgate so he could let himself into Mr. Robinson's cell. At that point, the inmate was found hanging.

Lawyer Saul Froomkin QC, representing the dead man's mother, Dedona Grant, expressed concern over the policy.

"Why is it at night, basic prison officers don't have keys to unlock? So if something traumatic is happening in a cell they have to find the divisional officer and he has to go to wherever the keys are and bring the keys to wherever the crisis," he inquired of Mr. Downie.

The witness, who is now a principal officer, replied: "It's a security policy."

"Would you agree with me it's a stupid policy?" inquired Mr. Froomkin.

"I can't say," replied the officer.

"Would you say it's a good policy?" pressed the lawyer.

"I would say it's a good policy because it's a check and a balance for us as officers" replied Mr. Downie.

Mr. Froomkin, who stated that he did not understand this rationale, continued: "What's bothering me is if a prisoner was choking, the longer the delay between the time he starts choking and the time you get to him is critical. And I suspect that we will hear that Lorenzo actually strangled himself that is he didn't hang himself, his neck didn't break. If that's true, would you agree with me that the longer delay that someone is strangling the less likely it is that he could have been saved?"

Mr. Downie agreed. He is due to continue his evidence to the inquest today.