Kevin Keegan today resigned as Newcastle United manager, bringing to an end his second spell in charge of the crisis-hit English Premier League side.
The 57-year-old former England boss, who had only been at the helm for eight months, felt he was left with no option but to quit after falling out with the board over transfer policy.
"I've been working desperately hard to find a way forward with the directors, but sadly that has not proved possible," Keegan said in a statement.
"It's my opinion that a manager must have the right to manage and that clubs should not impose upon any manager any player that he does not want.
"It remains my fervent wish to see Newcastle United do well in the future and I feel incredibly sorry for the players, staff and most importantly the supporters. I have been left with no choice other than to leave."
Keegan's future at the club had been in doubt all week and his departure was widely expected after he missed training for the third successive day today.
The club are believed to have gone against Keegan's wishes by trying to offload both England striker Michael Owen and Joey Barton, the midfielder who served a prison sentence this year for assault.
The northeast club had insisted on Wednesday that Keegan was still their manager but revealed he was discussing the situation with owner Mike Ashley.
Some reports said Keegan - whose position was brought into question when Dennis Wise was appointed director of football in January without his knowledge - was disgruntled at Newcastle's failure to make any major signings during the transfer window, which closed on Monday.
The club's only business on deadline day was the 5.7 million-pound ($A12 million) signing of Spanish striker Xisco and the loan signing from Valencia of Ignacio Gonzalez, although Keegan had reportedly not expressed an interest in either player.
In a statement released later today, the club said: "Newcastle United Football Club is sad and disappointed that Kevin Keegan has resigned.
"Over the last few days, the club has devoted itself to the discussions it has held with Kevin and as a result of those discussions, had put together a set of practical suggestions for how to move forward.
"Today, the club made it clear to Kevin that if he had any outstanding concerns on its proposals, he should raise them with the club. The club regrets that Kevin has, instead of taking up that offer, chosen to resign."
The Magpies currently lie 11th on the table after a mixed start to the new season. They held Manchester United to a 1-1 draw, beat Bolton 1-0 but lost 3-0 to Arsenal.
Keegan is the second Premier League manager to quit in successive days following Alan Curbishley's resignation at West Ham on Wednesday.
Keegan's departure leaves the Magpies looking for their sixth manager in four years.
There were angry protests at St James' Park at the prospect of the adopted Geordie leaving the club for a third time after his time as a player and then as manager between 1992 and 1997.
Keegan has been idolised on Tyneside since he led Newcastle to promotion to the top flight as a player in 1982.
He took over as manager for the first time in 1992, once again leading them to promotion before narrowly missing out on the title in 1995.
But in 1997 he quit to be followed in the hot-seat by Kenny Dalglish, Ruud Gullit, Sir Bobby Robson, Graeme Souness, Glenn Roeder and Sam Allardyce.
David O'Leary and Everton's David Moyes are amongst the favourites to succeed Keegan.
