Keegan tonight resigned his post at St James's Park after days of speculation surrounding his future at the club.

And Barton - who played under Keegan during his first spell as Newcastle manager - believes the lack of input his old boss had in transfers was at the crux of his unhappiness.

Barton also warned owner Mike Ashley that the protests of recent days will be dwarfed by the outpouring of emotion tomorrow, as the news sinks in.

"I think it's been simmering, particularly in the last four or five days," said Barton, who became the most expensive defender in English football when he joined United in 1995.

"They had meetings over the weekend, and in the early part of the week, and I think if the board thought they had protests on Tuesday or Wednesday, wait until tomorrow.

"The fans will be bitterly disappointed with what's gone on, and the way it's all been handled.

"Eight months ago I was excited about Kevin Keegan taking over. We started to see signs of them doing well towards the end of last season, and they had a good performance at Old Trafford. They had a home win as well, and things were looking good.

"For one, I feel sorry for the fans, but I feel sorry for the players as well.

"This now throws it into utter chaos, because whoever takes over - apart from one person, Alan Shearer - is under immense pressure."

Barton feels Keegan, given his long-standing relationship with the club and its fans, was the ideal man for the job.

The 39-year-old went on: "Most importantly, Kevin knows that club. He knows what the fans, and the people in that area, want.

"He's stuck by certain players through thick and thin, and the players respect him.

"Now, he'll be very disheartened by what's happened, because he thought the club would allow him to go on and win things.

"He was hoping to get a large sum of money - that hasn't materialised.

"The owner is obviously a very wealthy man, but (Keegan) has been dictated to by certain people above him, and that's annoyed Kevin.

"Kevin's used to managing clubs - not necesarily finance and agents,he doesn't want to get involved with that - but he wants to get the players he wants, and to get the best out of them playing the style of football he wants, and he hasn't been allowed to do that."

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