From the shadowrun Wiki:
Lyonesse is an island that appeared in the English Channel on October 31, 2062. The Royal Navy have cordoned off the island and an SAS squad is stationed there. Great Form elementals provide additional security. Lyonesse is located where the Stalker Ley and Stonehenge Ley meet.
The island rumored to have a magical aura in flux, as if the island is not really a part of either the physical or astral worlds. It is named after the home of Tristan of Arthurian legend. The legendary Lyonesse sank into the ocean and its rise would signal the return of King Arthur. Many Brits have linked the new island to this legend and believe that a new age for Britain is forthcoming.
Index
Loose Alliances, 77
Runner's Companion
Shadows of Europe, 195, 207, map: 194, 206
Sixth World Almanac, 88, 156, 157, map: 146, 159