Update: It looks like Wikipedia has finally been revised to reflect the fact that the claim that the Wiener Library defends G. K. Chesterton from the charge of antisemitism is a myth. Whereas previously the entry in Wikipedia simply stated that the Wiener Library has defended Chesterton against the charge of antisemitism, it now states:

In his 1989 biography of Chesterton, Gilbert: The Man who was G.K. Chesterton, Michael Coren quoted the Wiener Library as having said that they had never thought of Chesterton “as a man who was seriously anti-semitic”. In 2010, the then director of the Wiener Library denied that either the library or anyone authorised to speak on its behalf had ever issued such statement. In September 2013, following a discussion of the issue on twitter, Coren stated that the disputed quotation had come from a 1985 conversation with a librarian whom he did not name. Although he did not explicitly withdraw his attribution of the quotation to the Wiener Library, neither did he provide any justification for regarding the unnamed librarian’s opinions as being those of the library’s.  http://en.wikipedia.org/wiki/G._K._Chesterton  (downloaded 14/10/2013)

Unfortunately, the myth that the Wiener Library has defended or does defend Chesterton continues to maintain a presence on the internet (though maybe this will disappear over time). The following are just a handful of examples (all checked 14/10/2013):

http://www.secondspring.co.uk/spring/semitism11.htm

http://www.secondspring.co.uk/economy/chesterton-anti-semitism.html

http://en.metapedia.org/wiki/GK_Chesterton

http://americanchestertonsociety.blogspot.com/2008_07_01_archive.html

http://criminalbrief.com/?p=10402

http://www.angelfire.com/folk/richardjgill/introduction.html

http://www.independent.ie/opinion/letters/authors-not-antisemite-2052470.html

http://timworstall.typepad.com/timworstall/2005/04/chesterton_and_.html

http://insightscoop.typepad.com/2004/2008/07/was-g-k-chester.html