Who is Helen and Margaret from London Transports and what is their importance? London_Transports English & Literature Helen and Margaret | London Transports

Margaret is a shoplifter, who for nine years has been making monthly "shopping sprees" (p. 133) without being caught. She makes sure that she always carries enough cash to pay for the items on her list in case she is caught, and has a careful methodology to minimize her risk, including studying items carefully in various lights, dropping them surreptitiously without looking down, asking the "Pay Here" person where some other item is located. She supposes that she could most easily talk her way out of trouble if she were caught by stealing only one item per store, so she spends much time checking bags of stolen merchandise into the luggage lockers of each new store she visits.