She won a scholarship to Bedford College at London University, worked for the Red Cross, then married David Gardam, a barrister, whose career was to provide much of the material for “Old Filth.” The day her third child started school, she said she sat down and began to write.

“I always had this feeling that if I took my attention away from the children, something bad would happen,” she said. “So I waited.”

After Ms. Gardam finished her first novel, “A Fair Few Days,” written for children, she walked up the road and posted it to the publishers Hamish Hamilton. “After three weeks,” she said, “I rang them up, and said, ‘I haven’t heard from you.’ Afterwards, I learned that they thought they had a crazy woman on the phone.” But fortunately, someone at the publishing house found the manuscript, she recalled, “and said, ‘You know, I think this might do.’ ”

Ms. Gardam wrote steadily from that time on; to date, she has published 16 novels (some for children) and eight short-story collections. She was shortlisted for the Booker Prize (for “God on the Rocks,” in 1978), and twice won the Whitbread Book of the Year, among other awards.

Ms. Gardam’s books are at once contemporary and satisfyingly crammed with old-fashioned narrative intrigue. “People die, wars come and go, houses rise and fall, people go mad and come back again, children grow up, whole continents are traversed,” the critic and writer Courtney Cook wrote in an email. But, she said, the “prose is spare and understated — so you get the high adventure of Dickens with the deft lightness of a late-20th-century author.”

Since 1987, Ms. Gardam has lived here in Sandwich, a pretty market town close to the southeast coast, a leisurely two-hour train ride away from London. Her house, in which she has lived alone since her husband died in 2010, dates, in part, to the 14th century (“Chaucer may have stayed here on his way to Canterbury,” she wrote in an email. “Whoever can tell?”), and has a glorious walled garden, filled with flowers.

The inspiration, perhaps, for Betty’s superb garden in the Old Filth books? “Betty would have managed it better than me,” Ms. Gardam said, referring to Filth’s wife, the central character of “The Man in the Wooden Hat,” the second novel in the trilogy.