York City manager Billy McEwan has left the Blue Square Premier club.
He was appointed as the Minstermen's boss in February 2005 after eleven and half years as a coach at Derby County.
A club statement on the club's website: "It is with regret that York City Football Club has parted company with manager Billy McEwan.
"Billy has been instrumental in the turnaround in the playing fortunes of the club, with last season's play-off position the major highlight."
Reserve team coach Colin Walker will take on the responsibilities of caretaker manager.
McEwan took charge at York when the former Football League club was facing possible relegation to Blue Square North level.
After securing their survival, he led City to eighth place the following season and then last season took York into the play-offs as they finished fourth.
However, top-scorer Clayton Donaldson moved to Hibernian and player-of-the-year Neal Bishop to Barnet and McEwan's rebuilt squad has struggled this season.
York lost at home to Havant and Waterlooville in the FA Cup first round and last Saturday's seventh home league defeat of the campaign to Salisbury City proved the final straw.
McEwan's first coaching appointment was at Sheffield United were he later took over as manager, before taking a similar position as manager of Rotherham United guiding them to the fourth division championship in 1988-89.
He later had a spell as manager at Darlington and assistant boss at Scarborough.
McEwan's playing career as a midfielder was spent with Hibernian, Blackpool, Brighton, Chesterfield, Mansfield, Peterborough and Rotherham.