The contents of a
well-used but badly flushed lavatory, the
bangers (sausages) being the turds and the
mash (mashed potato) being the bog roll.
"Cinders and
ashes, Thomas, your coaches are a disgrace", cried the Fat Controller. "There's soot all over the
windows, used tickets all over the
floor and Clarabel's khazi is full of bangers and mash!"