THE fracture was sudden but almost inevitable.

The departure of Alan Thompson, first-team coach, from Celtic at the weekend was the final step in a relationship that was heading in different directions.

Celtic made the official announcement yesterday in a brief statement. It read: "Celtic Football Club can confirm that Alan Thompson has left the club. We can also confirm that a meeting was set up between Alan Thompson and Neil Lennon on Sunday in Newcastle. However, Alan refused to meet with Neil, hence the reason for the discussion being conducted by telephone. The matter is now in the hands of lawyers and, therefore, we are unable to go into any further details."

Thompson's lawyer, Margaret Gribbon, of Glasgow-based Bridge Litigation, said: "I can confirm that I have been instructed to act on behalf of Alan Thompson following his dismissal by Celtic FC. Alan was informed of the decision to terminate his employment with immediate effect in a telephone conversation with the club manager Neil Lennon."

It was the final blow for the Englishman in what has been a turbulent spell, including losing his driving licence after pleading guilty to a drink driving charge. It is thought his relationship with the manager has become increasingly strained and that the departure did not surprise other members of the coaching staff.

It also signifies a rupture in a personal and professional partnership. Thompson was appointed by Lennon in June 2010 alongside assistant manager Johan Mjallby following the sacking of Tony Mowbray earlier that year. Thompson previously won four Scottish Premier League titles and five domestic cups as a player during a six-and-a-half-year spell at Celtic.

Thompson had impressed as a coach at Newcastle United's academy and Lennon was keen to use the Englishman's talents at Parkhead. However, the bond has disintegrated, with Lennon determined to forge on without his former team-mate. The manager has shown himself to be intensely focused, particularly in the run-in to his first title success. He wants to repeat it and now Thompson has been deemed surplus to that requirement.

The first decision for Lennon will be whether he needs to replace the coach. Celtic will assess the situation over pre-season, with the players returning to the club on July 2. The Champions League qualifying process for the club starts on July 31 and the Clydesdale Bank Premier League season begins on August 4. Celtic will play a challenge match against Real Madrid in Philadelphia a week later.

It is highly possible that Lennon will decide that with Mjallby and Garry Parker in the dugout he has enough cover. He has also the option of promoting from within the club with Stevie Frail, Chris McCart and John Kennedy all employed in coaching roles. He is restricted in the options form outside the club as he must have someone he can trust. Managers can be easily destabilised from within and loyalty is a quality that is put at a premium.

An intriguing possibility is that Lennon could opt for an older mentor as first-team coach. He resisted any attempt to install such a figure when he was appointed manager but may now feel that a championship gives him the confidence to bring in experience without compromising his future.

The Celtic manager, though, will be comfortable with continuing to shoulder the burden of being the prime tactician on the training field. The enduring image of Lennon as a frenetic presence on the touchline disguises the truth that he is a deep thinker about strategy and training schedules. Most of the precise coaching is conducted under his aegis and he was the instigator of the change in formations that peppered the season. As a tactician, he is particularly drawn to the option of playing with three central defenders with two full-backs pushing on.

Unlike his mentor Martin O'Neill, Lennon is a constant presence on the training field. While O'Neill was content to let Steve Walford, his constant coach, to work with the players on a daily basis, Lennon is a hands-on manager who wants to be involved in all elements of the job. He regularly attends matches in Scotland and England and has regular talks with his scouting department and enjoys a close relationship with its head, John Park. He has often been accused of playing hard but he works hard too.

The dissatisfaction with the input of Thompson and the subsequent pressure increasingly and inevitably led to the breach on Sunday. It may leave Lennon short of a coach but is a grievous personal and professional blow for Thompson who now has to rebuild a career after the high of a championship-winning season.

For Lennon, the way is clearer. He has been unashamed in stating his ambitions for the club, stating strongly he wants to follow in the footsteps of Jose Mourinho and Pep Guardiola as a young coach who scales the heights. Lennon, 41 this month, was erroneously linked this week with the vacant post at Norwich City and the Northern Irishman believes his ambitions, particularly in European competition, can be satisfied at Celtic.

There is a strong drive within the Celtic manager and he has set his sights high. Inevitably, there are casualties when this aim collides with those who do not share the vision. Thompson was in the line of fire at the weekend.