"He had leukemia and it triggered all sorts of other problems," she recalls. "A wound in his leg became excruciatingly painful, for instance, but because it wasn't actually a tumour that was causing the pain, the local doctor wouldn't prescribe morphine.
"One night he was in a terrible state, he was weeping because the pain was totally out of control. It was awful to see, here was a strong, highly intelligent man reduced to a frightened wreck.
"In the morning my mother and I got him into hospital, and they promised us that he would be given morphine. That was about lunchtime. We waited until 4pm - no morphine. It was only the next day that they began to sort out the pain."
Herself a cancer sufferer, Becky Miles is founder and chair of the National Cancer Alliance, a lobbying group for better oncology services.
"I had to make an enormous fuss to get my father the care and drugs he needed, both then and later on. I am privileged because I have got both expertise and a lot of highly placed contacts. A less well-placed person would have been in a hopeless position.
"Patients can help themselves by finding out about pain relief, and they should feel confident to ask for changes when they see things are not working. And they must realise that morphine is not some evil substance that will leave them like zombies - it can be their best friend."