Put in a segregated cell for her own protection, Sarah, who had been off heroin for eight months, took an overdose of prescription antidepressants and died hours later in a Manchester hospital.
"The death was not a suicide," said Campbell. "It was quite clear that my daughter did not intend to die. It was a cry for help."
Her inquest found that avoidable delays and a failure in the prison's duty of care contributed to her death.
"Everything they could have got wrong, they got wrong," Campbell said.
"It was a Saturday afternoon and Sarah, despite being on suicide watch in the segregation punishment block, somehow managed to ingest a quantity of tablets.
"But then she told prison staff what she had done. And the prison staff, including a nurse -- it's hard to believe -- walked out of the cell and locked the door, leaving Sarah unattended.
"Then there was an argument between a prison officer and a nurse about whose job it was to call an ambulance. Somebody else went off to look for some handcuffs.
"When the ambulance arrived at the prison gates it was held up for eight minutes before they let it through.
"By the time paramedics got to Sarah she was unconscious. She was taken to Wythenshawe Hospital, where doctors from three specialties tried to save her life, but she died at 7:56 p.m."
Since her daughter's death Campbell has led 26 protests at prisons where women have died.
"The only way I can deal with my anger and grief is that I hold prison death demonstrations," she said.
"We should not be having women suffocating themselves, hanging themselves, poisoning themselves when in the so-called care of the state."
Last year just three women died from self-inflicted deaths in prison, down from 14 in 2003, but so far this year the total has risen to seven.
Last week Campbell was in action again, upbraiding Jack Straw at a meeting of the Howard League for Penal Reform, where she is now a trustee.
"Since my daughter's death four years ago we have had 39 dead women prisoners. For a so-called modern Labour government this is utterly disgraceful," she told him.
Straw, who acknowledged that his reply would be little comfort to Campbell, said he and everyone in the prison service was concerned about women's self-inflicted deaths.
He said the Ministry of Justice would work with the Howard League and other organisations on the problem.
"I don't pretend we have a monopoly of wisdom on what kind of conditions are most likely to ensure that the depression that people can feel almost inevitably when they go to prison is not translated into self-inflicted harm or death," he said.
Afterwards Campbell said she was overwhelmed and close to tears from the emotion of the encounter.
"I want an end to women dying in the so-called care of the state.
"It takes me a lot of energy to stay calm and focused and say what I want to say without blowing my top."
