European laws on discrimination could see Old Firm fans banned from wearing their strips to work, BBC Scotland has learned.
From the beginning of December, religious discrimination in the workplace will be targeted by legislation which may stop workers displaying an allegiance to Celtic or Rangers.
The move will make it illegal to discriminate in the workplace on grounds of religion - and Old Firm strips have become symbols of religious adherence for many.
It is feared that when the new law comes in, employers may face compensation claims from workers who feel harassed by rival colours.
Alan Masson, an Edinburgh employment lawyer, said he has been advising clients to steer clear of allowing football strips in the workplace.
Mr Masson told BBC Scotland: "The strips are seen as symbols and they become the aggravating fact, they are the genesis of the harassment that takes place, the catalyst that gets it all going.
"If everyone was just working alongside each other wearing ordinary clothes it would not be as in your face as it is with people proudly wearing badges of their belief."
Liberal Democrat MSP Donald Gorrie, who campaigned against sectarianism, said: "I have mixed feelings about this. I think it is a bit heavy but I can see why they are doing it.
"Measures are already in place in a lot of clubs, schools and pubs against wearing sport shirts - especially Rangers and Celtic.
Britain already outlaws discrimination over race, gender or disability."
The new move is part of a continuing programme which affects other types of discrimination.
From next month It will be unlawful to discriminate on grounds of sexual orientation, and from 2006, it will be illegal to pick and choose between workers on age grounds.