What is a 'chip-butty running'?
Belows are from THE TAKING OF ANNIE THORNE by C J Tudor.
"I stare down at PC Cheryl Taylor. Her tone is brusque, her demeanor cool. I get the impression that she would rather not be here. Perhaps I'm keep her from a major heist, or the evening chip-butty run."
I wonder what a 'chip-butty run' means here.
Thanks in advance! :)