Ashley told the News of the World: "I want a team that will go all out to try to give Chelsea a walloping, that will try to stuff Tottenham and that will be brave and bold enough to attack Manchester United.
"To date I have invested £250million to try and make it happen.
"And I'm not the only one who could see it wasn't working with things as they were.
"So when my chairman (Chris Mort) told me it was time for a change I knew it had to happen. I just knew it was time for me to get involved.
"So I did what I should have done in the first place and decided it was time to run the club the way I wanted.
"I must admit that when I bought this club my gut instinct was to bring in my own team to run it straight away, including a new manager.
"That's no reflection on Sam, that's just the way I have always done things.
"But for once in my life I ignored my intuition and, looking back, that was a mistake.
"Now is the time to put away my Newcastle shirt. I'm not saying I will never go back on the terraces but now I have to be in the boardroom - I have to be hands on."