Two prison officers failed to protect a "mentally unstable" inmate who took his own life after being left alone with a makeshift noose in an unlit cell, a court has been told.
Liverpool Crown Court heard Paul Fairhurst and Rachel Jameson did not act after being warned Anthony Paine was in danger at HMP Liverpool in 2018.
The 35-year-old, who had schizophrenia, took his own life shortly after.
Mr Fairhurst, 64, and Ms Jameson, 32, deny gross negligence manslaughter.
The court was told Mr Paine was put on a "basic regime" in the days before he died because of his use of spice, a synthetic cannabinoid, and was moved to a cell that had been painted a dark colour and had a broken window and no electrical light.
Duncan Atkinson KC, prosecuting, said the "unsatisfactory nature" of the cell for "a mentally unstable inmate does not appear to have been recognised by either of the defendants", adding that a nurse had described it as the "worst cell she had ever encountered".
He said in his final days, Mr Paine was not given his medication several times because his cell was too dark for him to be assessed by medical staff.
"By the time that these defendants had dealings with Mr Paine, [he] had harmed himself on a number of occasions," he said.
He said Mr Paine had been "difficult at times to manage", had appeared to be "abusing spice" and had been, "perhaps understandably, unhappy" with his cell.
He said the inmate was seen at 13:45 GMT on the day he died by prison officer Kristopher Mason, who reported he had made a noose.
Mr Mason said an "emotional" Mr Paine told him he had not had his medication, had no cell lights and wanted to see the prison chaplain.
The jury was told the officer persuaded the inmate to take the noose down but it stayed in his cell.
Mr Atkinson said in accounts given in 2018, Mr Fairhurst, a custodial manager, and Ms Jameson, a prison officer, accepted that Mr Mason, who had in post for nine months, reported what he had seen to them.
"Mr Mason was not given further instructions by either of them," he said.
"There is no note of any other measure being taken at that stage."
He said the jury "may conclude Mr Mason would have been entitled to believe that these more senior and more experienced officers knew more than he did," but the discovery of a noose was a "critical moment in the chronology".
"Beyond his earlier acts of self-harm, including a number that day, Mr Paine had now deliberately made, and still had, what each defendant understood to be a noose or ligature," he said.
"There was to be a period of time when he would, if no steps were taken, be alone in his dark cell with that ligature."
He said the situation was an "immediate suicidal crisis", according to guidance and training, but Mr Fairhurst and Ms Jameson did nothing.
The court was told Mr Paine told Mr Mason at 14:26 that he had thrown the noose out of the window, but when the officer returned to the cell just before 15:00, the inmate had killed himself.
Mr Atkinson said both defendants had breached "the duty of care that they owed Mr Paine" and their lack of action showed "a significant failure on the part of each to take obvious and straightforward steps".
Mr Fairhurst, of Chorley, Lancashire, and Ms Jameson, of Prescot, Merseyside, also deny an alternative charge of failing to discharge general health and safety duty at work contrary to the Health and Safety at Work Act 1974.
The trial continues.