A disabled woman suffering a severe asthma attack died after waiting 39 hours on a chair in a busy A&E for a hospital bed.
Marina Young, 46, was taken to the Royal Preston Hospital, in Lancashire, suffering shortness of breath and a headache.
Doctors quickly realised she would need to be admitted, but the hospital was full, with more than 50 people waiting in A&E for a bed on a ward.
Staff underestimated the severity of her condition, and failed to give her specialist drugs or refer her to critical care or respiratory medics.
Marina spent two nights in a chair and, around 10am on the second morning, was found collapsed, still fully clothed and soaked in her own urine.
She went into cardiac arrest and staff tried to resuscitate her.
But when her sister, Michelle Young, 47, arrived a short time later to drop off some belongings, she was given the devastating news that Marina had died.
An internal investigation by the hospital found that Ms Young, who suffered from spina bifida, would not have suffered a cardiac arrest if she had received more timely treatment and been referred to senior doctors sooner.
Michelle, a retired hospital ward sister, told MailOnline: 'Marina died in horrific circumstances.
'It is sickening to think that my sister could be treated with such a lack of compassion by the NHS, which is supposed to care for all people, irrespective of their physical limitations.'
Marina was diagnosed with spina bifida, which can cause lifelong mobility problems, at birth. She was the first baby in the UK to undergo a bladder transplant.
Despite her problems she managed to live independently, could walk short distances and was close to her family.
On the evening of June 20, 2022, Michelle drove Marina to the Royal Preston because she felt wheezy and suspected she was suffering from an asthma attack.
When they arrived, at 7.25pm, Michelle explained her sister's medical history to nurses and, although she wasn't allowed to stay because of Covid-19 restrictions, was in regular contact via text messages. The texts reveal Marina's mounting distress, Michelle said.
In one Marina, who had a fear of hospitals because of her experiences as a child, wrote: 'Scared at night sitting in a chair with a pounding headache.'
The investigation found that Marina was seen by a doctor around 9pm and at just before 11pm on June 20, when a decision was made to admit her to a ward.
But A&E was extremely busy that night, with 109 people in the department and around half waiting for a bed.
Although Marina was given antibiotics for a suspected infection, there was a delay in administering nebulisers — drugs to treat asthma — and a failure to repeat blood oxygen tests.
There was also a delay in her being seen by a senior consultant and a referral to the hospital's respiratory team the following day was not actioned.
Although further tests in the early hours of June 22 showed no improvement in Marina's condition and that she was suffering 'life-threatening asthma', her care was never escalated to the hospital's critical care team.
At around 9.25am on June 22 Marina, of Ribbleton, Lancashire, was reviewed by a trainee medic, who noted she was 'speaking in short sentences but was visibly breathless'.
She was seen by a nurse at 9.44am but three minutes later was found collapsed in her chair in cardiac arrest.
Medics tried to resuscitate her but she could not be saved.
Michelle said she hoped an inquest into Marina's death, due to take place later this month, will shine a light on the way disabled people are treated by the NHS in the hope lessons are learned to stop other families suffering like hers.
She added: 'Losing Marina in such an appalling way has been profoundly devastating not just for me, but also our dad, George, who Marina cared for while he was undergoing cancer treatment and has sadly since passed away. I believe our dad's death was contributed to by the stress of what happened to Marina.
'We hope as a family that this inquest process leads to change and to the avoidance of anyone else going through what we have had to endure.'
Madeleine Langmead, a medical negligence solicitor at law firm JMW, who is representing Marina's family at the inquest, said: 'Marina was a much-loved sister and daughter and her death has had a catastrophic impact on her family.
'Nothing can bring Marina back but it is vital that she is given a voice and that her care is scrutinised.
'Marina was a vulnerable patient and her case could have wider implications for patient safety.'
The firm will also be evaluating whether any legal claim for compensation can be brought against the hospital.
A spokesman for Lancashire Teaching Hospitals, which runs the Royal Preston, said: 'The Trust would like to offer its sincere condolences to the family and friends of Marina Young.
'We welcome the independent scrutiny of the coroner and are committed to any further learning that is developed as a result of the inquest.'
Significant waits in A&E have been linked to excess deaths and increased harm to patients, as their condition can deteriorate before they are admitted or given a bed on a ward.
In 2022, 23,003 people died after spending at least 12 hours in an A&E waiting for care or to be admitted to a bed, according to the Royal College of Emergency Medicine (RCEM), equating to roughly one person every 23 minutes.
Earlier this year Inga Rublite, 39, died after being found unconscious under a coat on the floor of a hospital A&E department, where she had been for eight hours.
Her name had been called three times by staff at the Queen's Medical Centre, in Nottingham, but when she failed to respond, they assumed she had left and discharged her from the system. She had suffered a brain haemorrhage.