Ashley has pledged to become a more hands-on owner

The billionaire, who has invested �250m so far, was speaking as he defended his decision to sack manager Sam Allardyce.

"I had to act, and I did what I should have done in the first place," he told the News of the World.

"I must admit that when I bought this club, my instinct was to bring in my own team to run it straight away, including a new manager," he said.

"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 have to be hands on Mike Ashley

Newcastle had hoped to bring in Portsmouth manager Harry Redknapp to replace Allardyce who left the club after only eight months in charge.

But Redknapp said on Saturday that he had rejected Newcastle's "terrific" offer, and the club are still searching for a new manager.

Ashley, who is famed for wearing a replica Magpies shirt and sitting with the fans despite his vast wealth, says now is the time to take a more hands-on role at boardroom level.

"Now is the time to put away my Newcastle shirt," he said.

"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."

He said he is desperate to bring silverware to St James' Park, but more importantly he wants to see exciting football at Newcastle.

He said: "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."