Celtic chief Lawwell says sorry to supporters

Lawwell made the acknowledgement in a letter to season ticket holders as he urged them to continue backing the club despite a disappointing season following the appointment of Tony Mowbray as manager.

Celtic launched their search for a permanent successor to Mowbray last weekend after Neil Lennon ended his interim reign with an eighth consecutive Clydesdale Bank Premier League win. Mowbray was sacked in March after a poor campaign hit a new low with a 4-0 defeat by St Mirren, despite major investment in the squad in the winter transfer window.

Worse was arguably yet to come though as Celtic lost to Ross County in the Active Nation Scottish Cup semi-finals to ensure their first season without a trophy since 2003, when they had the consolation of a Uefa Cup final appearance.

Lawwell wrote: "This season has been one of the most difficult we have experienced in recent years. The club set out with great optimism at the start of the season, with a new management team and with the objective of refreshing the first-team squad and regaining the Scottish Premier League.

"These changes did not deliver the success we hoped for and ultimately, this season has been unacceptable. For this, we sincerely apologise."

Lawwell urged Celtic fans to help the club regain the SPL title from Rangers by renewing their season tickets, which have been frozen in price. Lennon is understood to be hopeful, but not optimistic, about his chances of replacing Mowbray full-time, while Scotland manager Craig Levein has declined to comment on speculation linking him with the post.