Bolton Wanderers have confirmed that Sam Allardyce has left his post at the Reebok Stadium after spending over seven years in charge of the club.
Allardyce, who was appointed manager in October 1999, leaves with immediate effect following newspaper reports on Saturday linking him with Manchester City.
He took over at Bolton when the club was in the second tier of English football, and guided them to promotion to the Premiership, via the play-offs, six years ago.
After two seasons of relegation struggle, the Trotters have been regulars in the Premiership's top-ten in the last four campaigns, and they played in last term's UEFA Cup.
Saturday's 2-2 draw at Chelsea left Bolton fifth in the table and on course to play in Europe again next term.
Allardyce told the club's official website: "After nearly eight privileged years with Bolton Wanderers Football Club, I would like to announce that, after careful consideration and dialogue with my close family and senior officials within the football club, I will be resigning as manager of the club with immediate effect.
"It was mutually decided that I step down now rather than at the end of the season, to give my successor the ideal opportunity to experience the preparation and build up of match-day in readiness of next season.
"The decision to leave the football club, which has been my spiritual home for over 18 years, as both player and manager, is one of the hardest decisions I have had to make in my life.
"However, after guiding the team into a position where the club is on the verge of qualification for European football for the second time in three years, which has been the accumulation of almost seven years of strategic building and hard work across all areas of the football club, I feel it is the right moment to step down from my duties and welcome a new exciting era for the club under different leadership."
Chairman Phil Gartside added: "I have reluctantly accepted the resignation of manager Sam Allardyce after eight years of unprecedented success at the club.
"I would like to thank Sam for his enormous contribution to Bolton Wanderers, both as a player, but more importantly as a manager.
"Since joining the club as manager in October 1999, he has helped lead a fantastic transformation of this famous Lancashire club and has helped design and build an infrastructure that will enable the club to continue the progress that we have undoubtedly made in his period of office.
"He has given his reasons for wanting to leave the club at this time, which are private and we respect that privacy."