They flap and lollop and squawk and scavenge. They hold the future of the realm, some say, in their fearsome beaks. And now one of them — their queen, Merlina — has been reclassified to MIA from AWOL, heralding the feared redemption of a purported prophecy dating from the time of King Charles II in the 17th century: When the ravens leave the Tower of London, the building will crumble and the kingdom with it.

That at least is the story so far, a blend of myth, invention and hard-billed commercialism that has elevated the resident colony of ravens at London’s famed prison and palace on the north bank of the River Thames to a rare status: clipped-wing guardians of the national destiny, tourist-dollar magnets.

Most people, including the tower’s scarlet-clad wardens known as Beefeaters, dismiss the prophecy wryly as a fiction invented in Victorian Britain in the 19th century.