Keegan quit his post as manager on Friday, less than eight months after taking charge of the club for a second time, citing differences with the club's board.

The 57-year-old did not have full control over transfer policy and consequently his relationship with owner Mike Ashley and London-based executive director of football Dennis Wise broke down.

The departure of Keegan has caused uproar among supporters, who demonstrated in large numbers against Ashley and Wise outside St James' Park Thursday night and Friday morning.

A boycott of the next home match against Hull on September 13 is being organised.

Newcastle issued a statement confirming Keegan's departure and stated they had tried hard to resolve their differences with him after three days of unrest, but there was no comment from the club on Friday.

Any new manager coming in would have to work within a structure which has been heavily criticised by the League Managers' Association.

The LMA worked with Keegan to try to reach a solution to his impasse with the board but without success.

LMA chief executive Bevan told Sky Sports News: "It looked a little bit like an orchestra with four conductors.

"They had everybody on the bus but they weren't on the same seats. It was going to break down sooner or later.

"If you look at a football club where people are running it from different parts of the country, where you have got a manager who doesn't know who has been signed, who's leaving and who's coming, it's a recipe for disaster."

Reports have suggested Keegan's departure could now lead to a court battle over compensation.

It is understood that Keegan's three-and-a-half-year contract contains a clause stipulating whichever party terminates the deal owes the other £2million.

Keegan, however, may argue that he has a case for constructive dismissal after finding himself unable to work alongside Wise.

Godwin Busuttil, a barrister at 5RB in London, explained: "I would guess the fault line of this argument is going to be Keegan saying, 'You Ashley/club have breached this contract first, you repudiated it by putting me in a position whereby I couldn't carry out my managerial, contractual functions.

"'You breached the contract. You put me in a position, you forced me to go. That is called constructive dismissal. Effectively, it means, I had no choice but to go'.

"The club would say, 'No, you resigned. You didn't have any good reason to do that. You breached the contract'.

"Unless they can sort out that difference between them, then a court will have to sort it out. A judge will have to decide the rights or wrongs, or perhaps an arbitrator."

LMA chief Bevan believes Newcastle would be better re-evaluating their managerial structure rather than pursuing legal action against Keegan.

Bevan feels the roles of Wise and the manager need to be clearly defined with areas where they overlap identified.

He added: "I think I'd like to see Newcastle - rather than coming out and saying they are going to sue Kevin Keegan for £2million - talking about how they are going to improve for the next manager, how to have a working executive team that has shared positions, shared goals and good communication.

"There are two things in a football club that need to happen.

"Successful clubs have good leadership at the top and they have a good recruitment process.

"They take on quality people who make sure there is a process in place so they have clarity of roles and they are all working together."