Celtic manager Neil Lennon has resigned with his side 18 points adrift of Rangers in the Scottish Premiership.
Lennon took charge for a second spell in February 2019 when Brendan Rodgers left and led the club to two titles, two Scottish Cups and a League Cup.
However, Celtic are well behind their Glasgow rivals in their bid to win 10-straight titles and slumped to defeat at struggling Ross County on Sunday.
Assistant manager John Kennedy will take interim charge of the team.
“We have experienced a difficult season due to so many factors and it is very frustrating and disappointing that we have not been able to hit the same heights as we did previously,” Lennon said.
“I have worked as hard as ever to try and turn things around, but unfortunately we have not managed to get the kind of run going that we have needed.
“I have always given my best to the club and have been proud to deliver silverware to the Celtic supporters. The club will always be part of me. I will always be a Celtic supporter myself and I will always want the best for Celtic.”
Celtic chief executive Peter Lawwell: “Neil has always been and will always be a true Celtic man and someone I will always hold in the highest regard. Personally, it is a sad day for me to see Neil leave. Neil is a man of quality and decency, he is someone who will always be part of the fabric of Celtic and someone who will always be welcomed.”