The
Hole-in-the-Wall Gang is a joking reference to any bum that hangs around a cash machine, ATM, or '
hole-in-the-wall'.
The name comes from the infamous
Hole-in-the-Wall Gang that operated out of Johnson County, Wyoming during the late 19th century.
Why these beggars ask for spare change by a machine that'll only provide notes of £10 or more, is generally not understood.