This seems to have been taken out of context and over-emphazed by both the Peter Singer ethics crowd and the most vigilent on the pro-life side. Those familiar with Anglican-speak understand that it is entirely unreasonable to expect any sort of unqualified remark to come out of the Church of England. (Truman's joke about the one-handed economist comes to mind.)
However, we must agree that while there may be cases such as the brain stem example cited above where there may be no reasonable expectation of sustainable life, this is a terribly slippery slope and we must always err on the side of life.
See previous post on this subject
http://www.freerepublic.com/focus/f-news/1737110/posts
The doctors group (probably a fairly secular one) called for euthanasia. The Bishop did not, but has had his statements linked to the doctors group to make it seem that he supports their viewpoint.