They strike in the dead of night and at dawn the population rises to a sinister peril.
London has joined the select band of world cities cursed by the mysterious phenomenon of manhole cover theft.
The target has been Newham, east London, where in recent weeks nearly 200 grates and covers have been stolen. The thieves made off with 93 covers in one week. Bemused council officials have been trying to locate and cover the holes before someone disappears.