In the clip, which has gone viral on social media, supporters were filmed singing “Up the Ra”.
The clip is thought to have been recorded on the day Celtic lost the Old Firm derby 3-2 to Rangers at Celtic Park.
A source told our sister title, the Scottish Daily Express, that Docherty is the person in the video.
They said: “Staff will not be very pleased by this. Celtic fans, Republicans and beasts are treated better than unionists in Glenochil prison.”
The song in the video, Celtic ...