- "Get out of my house this moment, you shameless hussy, or I'll send for the police."
- ―Letitia Ketterley to Queen Jadis [src]
Described as "a very tough old lady" with a "firm quiet voice", Letitia was likely was the first person other than Digory, Polly Plummer and Andrew to see Jadis when she arrived from the World of Charn.
Despite Jadis' fearsome appearance and extreme temper, Letitia was not intimidated in the least. Thinking she had come from a circus, and disapproving of her bare arms, Letitia immediately ordered Jadis to leave or she would inform the police.
When the witch tried to cast a spell and realized that her magic had no effect on Earth, Letitia further dismissed her as a drunk (mistaking the incantation for ordinary English). In anger, Jadis grabbed hold of Letitia and threw her across the room, though luckily she landed on a mattress that she had been mending.
After Jadis left the house with Andrew and Letitia had recovered from the shock (which took only a few minutes), she ordered Sarah the housemaid to go to the police station and warn them that a "dangerous lunatic" was out on the streets.
Despite her tough exterior, Letitia was a clearly a loving person: She was very distressed over the declining health of Digory's mother,  and when Mrs. Kirke miraculously recovered (thanks to the silver apple that Digory brought back from Narnia), Letitia did everything she could to make her happy.
Letitia's relationship with her brother Andrew was not as amicable. While the specifics were unclear, Andrew's extravagant spending and lack of regular income over a thirty-year period had forced Letitia to cover his expenses repeatedly.