Derry played for Warnock at Bramall Lane.
He recalled on the Football Gods podcast: “It was bizarre. When I was coming through Notts County as a 16-year-old Neil had left by then and gone on to manage a different club. I had four years at Notts County whilst Neil wasn't the manager, and then I went to Sheffield United as a 20-year-old and when I was 22, Neil then started his career at Sheffield United.
“As much as I'd watched his teams throughout my junior years and had the chance to work under a manager I'd watched in the past, we actually didn't hit it off.
“We had a big, massive argument and he ended up selling me after about three months of being at Sheffield United. He sold me to Portsmouth and then many years later, brought me back to Crystal Palace as a 30-year-old and then onwards to QPR.