Fed-up Green Brigade members have warned Celtic their fight to keep Bernard Higgins out of the club is far from over.
The former Police Scotland big-hitter played a major role in the implementation of the controversial Offensive Behaviour at Football Act.
And he has been reportedly lined up for a security role at Parkhead - something a section of the club's support is deeply opposed to.
Celtic's Ultras have been dead against it and have led protests on several occasions over the last couple of weeks.
Now the fans' group have released a strongly-worded letter as they insist the fight goes on with 90 minutes of silence during the Motherwell game.
And they also have acting chief executive Michael Nicholson in their cross hairs over a lack of correspondence regarding Higgins' potential employment.
A statement read: "Over recent weeks, the Celtic support has united to send a clear message to the Celtic board that Bernard Higgins is not welcome at the club.
"An open letter sent to Michael Nicholson, co-signed by ever supporter group and organisation, all prominent fan media outlets, podcasts and websites, and over 250 supporters clubs made it clear that fans oppose the Higgins appointment and will refuse to engage with him.
"Michael Nicholson has not responded.
"An email campaign was launched, with individual supporters contacting Michael Nicholson directly to demonstrate their personal opposition to Higgins' appointment and demand a response.
"Michael Nicholson has not responded.
"The same signatories to the open letter - and more - displayed banners around Celtic Park reiterating their opposition to Higgins' appointment.
"The club has not responded.
"Since the appointment was first discussed in October, continual requests have been made to the club to discuss this issue further.
"The club has not responded.
"It is within this context, and with regret, that we announce a return to the silent protest which began the campaign. On Thursday against Real Betis, and if necessary, on Sunday against Motherwell we will remain silent for 90 minutes and ask those who support the campaign to join us.
"We will gladly call off Sunday's silent protest should Michael Nicholson agree to meet with the supporter organisations to discuss the issue.
"We hope that he will finally take us up on this request and the protest can be avoided.
"At a time where there is a growing bond between the team, the manager and the supporters we are frustrated that the board continue to sow division.
"We desperately want to provide the vocal and visual backing that Celtic Park is famous for but feel unable to do so while the Higgins saga continues."
