King Solomon's Carpet Barbara Vine , Ruth Rendell

King Solomon's magic carpet is the London Underground, running past the disused old school building that houses the most ill-assorted covey that Vine (Ruth Rendell) has brought together since 
A Fatal Inversion
 for this updating of Conrad's novel of terrorist conspiracy, 
The Secret Agent
.

Tom Murray is a promising musician reduced to illegal busking in Underground stations and a sad little love affair with his accompanist Alice, who left her husband and newborn baby, taking only her violin. Together with Jasper Darne, another dropout from his family who likes to ride on the tops of Underground carriages, and Jed Lowrie, a Safeguard volunteer who's left behind his own family to live for his hunting hawk Abelard, they live in a failed schoolhouse--whose bell tolled for the only time in memory when the headmaster hanged himself from its rope.

The school's owned by the old man's grandson, Jarv Stringer, who now passes the time by writing a book on the Underground and taking in waifs and strays while his aunt Cecilia Darne, Jasper's grandmother, quietly declines around the corner under the variously watchful eyes of her relatives and her longtime companion Daphne Bleech-Palmer. The apple of discord in this extended, dysfunctional family is sinister Axel Jonas, who rides the trains with a dancing bear, actually a man named Ivan, until Jasper one day leads him to Jarvis's, where he takes up residence, seduces Alice, and begins to gather details about the operation of the Underground in preparation for a cataclysmic bombing.