Roy Keane has left his position as manager of Sunderland.
Sunderland confirmed the departure of Keane on Thursday, with players and staff at the Stadium of Light also informed.
“Roy’s decision sums up his desire to always do what is best for the club, despite the club’s efforts to keep him,” said chairman Niall Quinn.
“Roy deserves huge respect for his contribution and the manner in which he guided the club from the depths of the Championship back to the Premier League.
“His winning mentality and singled mindedness were just what this club needed. Even in his departure he has been more concerned for the welfare of the players and his staff than himself.
“The board has reluctantly accepted his decision and wish him and his family well for the future.”
The Black Cats are 18th in the Premier League and have lost five of their last six games. Sunderland’s latest defeat came against Bolton on Saturday, with the Black Cats losing 4-1.
“I ask myself every day if I’m the right man for Sunderland,” he said after that defeat.
“I asked myself this morning, and I said I was. Sunday morning, if the answer’s no, we’ll have to look at it.”
Keane had been locked in talks over a new deal, which he had refused to sign until he was fully happy with the terms.
The former Manchester United skipper took charge in August 2006 and he made an immediate impact as he led Sunderland to the Championship title the following May.
Last season the club consolidated their place in the top flight and Sunderland backed Keane in the close season by spending nearly £30million on new players with the likes of Djibril Cisse, Pascal Chimbonda, Anton Ferdinand, El-Hadji Diouf and George McCartney all coming to the Stadium of Light.
However, despite a morale-boosting Wear-Tyne victory over rivals Newcastle, Sunderland’s form and place in the league has plummeted, prompting the crowd to boo the team in recent weeks.
During his 12-year career at Old Trafford he earned himself a fearsome reputation as a no-nonsense tough-tackling midfielder. Keane also had spells at Nottingham Forest and Celtic, winning 66 caps for his country.