Dark Waters of Hagwood
From time to time I get hits from people searching for information about Dark Waters of Hagwood by Robin Jarvis. This sequel to Thorn Ogres Of Hagwood was due to be published in 2005 but there has been no sign of it, despite Amazon announcing a new publication date of February 2009 at the beginning of the year. I finally decided to email Puffin about this and they have confirmed that the series has been abandoned.
A great shame as Jarvis is a wonderful writer and I had high hopes for the series. He is still writing though and if you only read one anthromorphic mouse series make it the Deptford Mice trilogy (not the Deptford trilogy).
ETA: Apparently the book is written and Puffin have announced a new publication date of 2015 (see comment below) but since this is so far off I will continue to consider the book dead for the time being.
ETA 2: It lives! The book was published in 2013 and you can read my review at Strange Horizons.