An early-morning statement from the Parkhead club confirmed that Lennon had resigned from his role in the face of disastrous season for the club, in which their hopes for a historical tenth title in a row evaporated quickly due to their own poor form and Rangers’ rampant run.
Celtic also crashed out of the Champions League early to Ferencvaros, while suffering a shock Betfred Cup defeat by Ross County. They are currently 18 points adrift of their arch rivals and champions-elect Rangers in the Premiership.
Desmond and Lawwell have been huge supporters of Lennon and expressed sadness at his departure, hailing him as a man of “quality and decency”.
Lawwell, who stands down as chief exec at the end of the season and will be replaced by Dominic McKay, said: “I would like to pay tribute to Neil for all he has done for the club in his second spell, delivering our eighth and ninth successive league titles, the quadruple treble and winning the last five available domestic trophies.
“Neil has always been and will always be a true Celtic man and someone I will always hold in the highest regard.
“I have watched Neil fight many battles over many years, on and off the field, with a courage and tenacity few could match. Even this season, he has fought so hard and worked tirelessly to turn things around.
“While this season has not progressed as we would have liked, it cannot diminish the character or integrity of a man who has given the club so much.
“Personally, it is a sad day for me to see Neil leave the club. 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 at Celtic Park.
“On behalf of everyone at the club, and personally, I would like to thank Neil for his work as our manager and I wish him and his family good health and continued success in everything they do.”
Desmond added: “Neil is a Celtic legend both as a player and manager. He has given so much to the Club, and with his success over the last number of years – including winning a Treble in his own right – he will be very difficult to replace.
“We thank Neil sincerely for all he has done for the club and we wish him every success going forward.”
The Celtic board have placed assistant boss John Kennedy in temporary charge of the club while the hunt for a permanent manager continues.
Kennedy is the odds-on favourite with the bookmakers to be given the role on a full-time basis, with Scotland manager Steve Clarke, Belgium chief Roberto Martinez, ex-Bournemouth man Eddie Howe and veteran Champions League winner Rafa Benitez also linked with the vacancy.