When is a disclaimer allowable in a European patent application?

Various decisions of the European Patent Office (EPO) technical boards of appeal deal with this topic and have resulted in several referrals to the Enlarged Board of Appeal. A recent decision G2/10 of August 30, 2011 adds further case law and guidelines of how to comply with Art 123(2) and (3) EPC when amending the application during the substantive examination and the granted patent during opposition proceedings.