Relatives of patients who died unexpectedly at Stafford Hospital filled the front rows of seats at the start of the public inquiry into what went wrong.
Their despair, anger and frustration was palpable before Monday's proceedings got under way.
The inquiry follows a report which found appalling standards of care had led to 400 more deaths than should have been expected between 2005 and 2008.
One woman entered the inquiry room at Stafford Borough Council and left almost immediately, sobbing loudly.
Campaigners from the Cure the NHS pressure group have consistently called for a public inquiry, criticising a previous independent inquiry as "too narrow and private".
The public inquiry opened in two rooms at the council offices.
'Damaged by system'
One room contained the inquiry team and panels representing 13 "core participants" such as the Mid Staffordshire NHS Foundation Trust, the Department of Health and the Patients Association.
The hearing is being relayed to about 60 relatives and reporters in a fairly small second room, where large screens and speakers have been installed.
One man, whose father had died at the hospital, found having to sit in a separate room upsetting and shouted angrily that he wanted to "see the faces" of those who were giving evidence.
His interjection delayed the start of the inquiry while he spoke to the inquiry team in private.
Julie Bailey, whose mother died at Stafford Hospital and who founded Cure the NHS, said she could understand his frustration.
"These people have been damaged by the system," she said.
"They have been left so upset and pained by the NHS complaints procedure.
"I'm quite a strong person but I know I will never get all the answers about my mum's death. It's there daily, a horrible feeling that will never, ever go away.
"It's the knowledge that people have died needlessly."
She said the public inquiry was important because people would be compelled to give evidence under oath.
"We want to know what happened and why," she said.
Inquiry chairman Robert Francis QC paid tribute to Ms Bailey, adding that Monday was particularly symbolic as it was the third anniversary of her mother's death.
He acknowledged the "determination and courage" of the Cure the NHS campaigners who had pushed for the public inquiry.
In his opening statement, he said that "terrible standards of service inflicted upon so many of the patients" at the hospital and their families would be investigated.
Cure the NHS members sat together at the inquiry.
The group meets regularly at Mrs Bailey's cafe in Stafford and also holds social events.
The warmth and friendship between the members is evident as they share sandwiches in the break and discuss the inquiry.
Geoff Guest said the support of the group had helped him greatly.
He said his wife Irene died at the hospital and described her last weeks as "horrendous".
He said: "She was forgotten in the corner of the ward and her hair was not washed for weeks and her nails were left dirty."
Mr Guest travelled daily by bus to visit his wife and sadly watched her deteriorate.
He added: "All we want is justice and the truth to come out.
"We know what happened but what we don't know is how it happened".