He told the Evening Chronicle: "It has been a heart-wrenching decision for me to leave Newcastle again and that's why it took so long for me to make it.
"But everyone knows that my ambition is not only to be a manager in my own right some day but to be manager of Newcastle United, and to do this I knew had to move away again from St James' s Park.
"Don't get me wrong - I have loved every minute since I came back from Fulham.
"To be honest, there is not that much pressure being reserve-team manager and I probably could have stayed at Newcastle in that role for the next five, 10 or even 15 years.
"But I have always set myself targets and my ultimate goal is to be manage Newcastle United."