I don't know if this has a Glasgow equivalent. I was 18 years old, and two local hard cases were hassling me. My friend went and found Rob. Rob and I had been at school together as young children.
Rob appears and turns to the lads with a friendly smile
"A'right lads?"
Hard cases disappear faster than a shot of vodka in a Polish bar. Rob was affectionately known as "Buster". Years later, reminiscing on a long hot Sunday full of cider, he told me of his experiences in Borstal. The film "Scum" conveys something of the environment he described.