This guy has been digging huge tunnels under his house in London, and beyond to the neighbours house and under the road, for 45 years and the council are stepping in to fill them with concrete. Nobody's quite sure how far they stretch but in 2001 the pavement collapsed and you could see a few tunnels veering off underground. He's certainly got down to the water table. Mad story.
Derrick Schneider says:
There's an old book by Mick Jackson, called The Underground Man, about an old duke building tunnels under his estate (or having them built; can't quite remember). Perhaps it's an English affliction, though hopefully your guy doesn't go the same route as The Underground Man, who, if memory serves, ends the book with a self-trepanation (yeee).
From the Amazon.com write-up:
Through a fictional journal, Jackson constructs a portrait of William John Cavendish-Bentinck-Scott, fifth Duke of Portland (d. 1879), a prodigious eccentric best known for the elaborate network of tunnels he built beneath his estate. The duke is portrayed as a repressed hypochondriac, an old man morbidly curious about the workings of his body and mind. During the months encompassed by the novel, he grows increasingly obsessed with the fleeting bits of memory that intrude upon his ruminations and hint at some horrific, long-buried secret. A prime example of the psychological bent of the contemporary British neo-Gothic novel, this first novel from a British filmmaker and teacher of creative writing explores the darker fringes of consciousness. A subdued, though peculiarly compelling, tale. — Lawrence Rungren, Merrimack Valley Lib. Consortium, Andover, Mass.