Nottingham Forest have announced that manager Aitor Karanka has left the club after granting his request to be released from his contract.
There had already been rumours of unrest and the situation looked to come to a head on Thursday.
A club statement issued on Friday morning read:
"Aitor Karanka has asked to be released from his contract as the manager of Nottingham Forest Football Club. The club have agreed to this request and the terms of departure have been agreed. Both parties wish each other every success for the future.
"There will be no further comment from either party.
"Simon Ireland will take charge of first-team affairs until a new manager is appointed."
Karanka, who was an assistant to Jose Mourinho at Real Madrid prior to taking his first job in England with Middlesbrough in 2013, leaves Forest in seventh place in the Championship.
The club is four points off the all-important playoffs, with the New Year's Day win over leaders Leeds putting Forest back in promotion contention after a dreadful run of form in December - no wins in five straight games - had seen them fall away.
Forest are back in action on Saturday when they travel south to face Reading.