"We consider that the management team at Celtic FC are out of control and, in our view, this is evidenced by Mr Lennon's previous behaviour at Tannadice and at Tynecastle, for which he received a four-match ban, " said Smith's statement, referring to matches against Dundee United and Hearts.

BBC: Rangers Supporters Trust calls for Neil Lennon probe

The 30-year-old striker, who spent three seasons with Celtic, previously played for FC Twente and PSV Eindhoven.

BBC: Hartley and Dutchman leave Celtic

His firm acted for Celtic last season in a Europa League row involving FC Sion, which eventually saw the Scottish club replace the Swiss one in the competition's group phase.

BBC: Premier League clubs 'can meet Uefa financial rules'