A leading midwife who has led reviews into care failings in the NHS has criticised the health service for "failing" to give her daughter safe care.
Donna Ockenden, from Sussex, says her daughter Phoebe, who has epilepsy and was having seizures, was left in a chair on her own for seven hours after being transferred to hospital by ambulance.
Ms Ockenden led a review into maternity services at the Shrewsbury and Telford Hospital NHS Trust and is currently leading the probe into maternity care Nottingham University Hospitals NHS Trust.
The Department of Health and Social Care described Phoebe's treatment as "unacceptable".
Ms Ockenden said Phoebe had begun having seizures again after a nine-month gap when her medication was changed, and made three emergency visits in October.
Ms Ockenden said: "During the first two, I was with her and I was her advocate. It was still pretty rubbish.
"But for the third, I was in Dubai on holiday and woke up to messages about Phoebe being in A&E.
"Despite her learning disabilities and being known to the service, she was dropped off in the waiting room on her own. She is 20 but she is really vulnerable, and was left in a chair for seven hours still having some seizures.
"Initially she was left in the waiting area on her own. It's just unspeakable, it's absolutely disgusting and disgraceful."
Ms Ockenden also described helping other patients who had been left on trolleys, including an elderly lady calling for water and alerting staff to a confused elderly man who was trying to leave the hospital.
She said: "I'm desperately worried about this winter.
"Because I'm Phoebe's mum, I am praying fervently that she doesn't need to go into A&E any more but with her health complexities, we'll be very lucky if we get through the winter without her needing to go in."
Ms Ockenden did not want to name the hospital involved in her daughter's care.
A Department of Health and Social Care spokesperson said: "Phoebe's experience is unacceptable and is symptomatic of our broken NHS.
"The Chancellor has announced a £22.6bn injection into the NHS to get it back on its feet, so it can be there for all of us when we need it, once again."
Donna Ockenden will be interviewed on Woman's Hour on BBC Radio 4 at 10:00 GMT on 1 November, also available on BBC Sounds.