She said her mother Margaret Beckwith, who was then aged 64, had an appointment with Shipman at his practice, The Surgery on Market Street.
She said he had intended to give her mother medication and asked Ms Powell to leave the room so he could examine her.
However, she refused after feeling there was simply “something not right with him”, the 62-year-old said.
“He went to give my mum some medication and I said ‘she’s not taking it’,” she said.
“My mum asked me why and I said ‘can’t you see he’s no good? He fobs people off by telling different stories’.”
Ms Powell said she told Shipman, who was convicted in 2000, “I’m sorry. I’m not leaving” and he eventually wrote a prescription before the pair left unharmed.
“Whatever he wanted to do backfired on him because I was there,” she said.
