John and Ethel's son Stuart, a 53-year-old service engineer, said: "There is no forgiveness but I would not say there is hatred," he said.

"In the early days, I could have throttled Norris. He has ruined my life but taking justice in your own hands would end with me getting locked up.

"Norris is all the more dangerous because he has the experience and medical knowledge. It is all that much harder knowing that someone in what should be a caring profession did this.

"Now, I am very wary of hospital and hospital staff. I can't work out whether this was about (Norris] killing someone or being seen as a hero - by saving someone and being given glory for that. I don't think anyone will know the answer to that."

Of Ethel he added: "She was simply mother – always there when needed. Mother and father worked together their entire life."

Mr Hall added that his family still want a full public inquiry into procedures at the hospitals in Leeds. "There are still too many unanswered questions", he added.

Ethel Hall, whose parents owned a shop in Calverley, was born on February 9 1916 in Leeds.

She married John, a smallholder and dairyman, running a milk round in 1951 .The couple eventually took over running her parents' grocer's and butcher's shop in Calverley.

John, is now 88, but suffered a heart attack two weeks after his wife died – which his family blame on the stress of Ethel's death.