As a rule, the EPO examines only the formal conditions for claiming priority. The examining division (see points 155159
et seq.) normally checks whether a right to priority exists if it finds prior art (see point 32
) from between the priority date and the date of filing of the European patent application or if it finds a prior right under Article 54(3)
(see point 34
). The claimed subject-matter for which priority is claimed must be derivable directly and unambiguously from the full disclosure of the invention in the priority document.