Birmingham Children's Hospital has admitted that it caused a teenager to become paralysed from the waist down after a spinal anaesthetic was wrongly left in place for too long.
Sophie Tyler, 14, of Risca, near Newport, had gallstone surgery in the hospital in 2008. However, a pain-killing epidural infusion was not removed for two days, permanently damaging her spinal cord.
A day after the surgery, she complained of numbness in her right leg. And after two days of receiving the epidural, the numbness had spread to both legs and she was barely able to move her feet.
Hospital staff did not stop the pain-killing anaesthetic until the second night.
The following day, the teenager underwent an MRI scan, which revealed that the anaesthetic had entered the spinal cord and damaged membranes, paralysing her from the waist down.
Sophie spoke of how the horror at learning she would never walk again simply left her feeling "numb".
"Numb is how I felt. In the beginning it did not really sink in. It did not seem real at all," she said.
"That came later when I got home. Then a lot of people, friends and family, were really really good to me, but to be honest I didn't want to see anyone. I shut myself off from the world, it was just the family at that point."
Medics initially told Sophie and her family it was possible she might regain some or all of her mobility, but that proved false.