At first glance, as the author, Marcus Dunk, suggested, intelligent extra terrestrials back to their usual trick of crop circles, sprung to mind. However, this is in fact the 3 day work of a 25 year-old lady from West Yorkshire, who took to searching Google Earth maps as a way of passing time after an accident that left her house bound. She scoured winding rivers, hedges, fields, roads, buildings' anything that might throw up a shape to resemble the 26 letters.
'Q', was apparently the most difficult to find, but after a long search, it was found in the roof at Gatwick Airport. I second Rachel Young's comments that this is a nice way to celebrate our country.
It reminded me of a typography project I did for AS level graphics which involved creating the alphabet showing sensitivity to a particular theme. For anyone else that did or didn't do this course, it may well be worth trying this for yourself if ever you should fancy spending a few days inside.