Update 12:36
Neil Lennon has released a brief statement on his departure from Celtic.
I have parted company with Celtic.
The club are in a very strong position and I wish the fans and the club all the very best for the future.
I can't thank Peter Lawwell and the board enough for their backing and support during my time as manager.
11:57
Neil Lennon will step down as Celtic boss today according to various reports in the Scottish media.
BREAKING: From @tedermeatballs Neil Lennon to stand down as Celtic manager. Statement expected later today.
— The Daily Record (@Daily_Record) May 22, 2014
Neil Lennon is to leave as @celticfc manager after four years in charge. More to follow...
— Scottish Sun Sport (@scotsunsport) May 22, 2014
@scotsunsport understands the 42-year-old has decided to exit in order to seek a new challenge. Official confirmation expected later today.
— Scottish Sun Sport (@scotsunsport) May 22, 2014
Lennon was appointed appointed caretaker boss at Parkhead in March 2010 before being confirmed as Tony Mowbray's permanent replacement three months later.
As manager he won three league titles and two Scottish Cups along with being behind some heroic Champions League performances including beating Barcelona.
He has been continuously linked with the Norwich job in recent times.
Celtic legend Henrik Larsson who has coached in Sweden is the early favourite to replace the Northern Irishman.
Picture credit: Matt Browne / SPORTSFILE