Mr Calvert allegedly pressed his cell alarm 50 minutes before his death
A fresh inquest has been ordered into the death of a prison inmate who was found hanged in his cell.
Paul Calvert, 40, died at Pentonville Prison, north London, in October 2004. He had made previous suicide attempts.
The High Court quashed the verdict of a 2007 inquest which did not allow jurors to consider whether "neglect" by prison officers played a part in his death.
Officers allegedly ignored Mr Calvert's emergency cell alarm for 50 minutes, judge Sir Thayne Forbes said.
Father-of-two Mr Calvert was remanded in custody to Pentonville for breaching parole, the court heard.
He was detoxifying from a number of drugs at the time and Mr Calvert's solicitors were concerned that he was at risk of self-harm or suicide.
Mr Calvert was found hanging by a belt tied around his neck.
'Breach of security'
The original inquest jury was told to make "neutral, non-judgmental conclusions" about his death.
It ruled that Mr Calvert's death followed "systematic failures, incomplete paperwork, lack of communication, disablement of cell bells and breach of security".
But on Friday the High Court ruled that jurors had been wrongly deprived of the chance to consider the "key issue" of possible neglect by prison officers.
It was alleged that officers failed to pay attention to Mr Calvert's emergency alarm "because they were playing or watching a game of backgammon".
Mr Calvert's mother, Gwendoline, argued that the original inquest deprived her of the inquiry to which she was entitled under the European Convention on Human Rights.
The new inquest will take place "as soon as reasonably practical", the judge said.