They are used to keeping their pranks inside the dressing room but Si Ferry and Paul Slane made sure they roasted Open Goal pals Derek Ferguson and Frank McAvennie in public.

The two jokers had a film crew follow their mates into Slaters Menswear as they tried on new suits for their Keeping the Ball on the Ground podcast. Roping in actor Brett to play the tailor, he constantly calls Derek Barry, hilariously 'mistaking' the Rangers hero for his younger brother.

During another portion of the clip, Brett asks McAvennie to say, 'Where's the burds?' after his iconic charicature from BBC sketch show Only an Excuse - but Macca declines.

As the prank winds down, the finale has the pair - who expected freebies - looking shocked as they are told the final bill and that they were only to get 50 percent off. To which McAvennie demands: "Switch they cameras off". As Si and Slaney have a giggle in the backroom, they eventually emerge to put the Old Firm legends out their misery - to the delight and relief of the duo.

Watch the full brilliant video above. Warning: Strong language.

You can read Si Ferry's exclusive column in the Glasgow Times every Saturday.