5. Intervention of the assumed infringer 

Under certain conditions (see D‑VII, 6) third parties who prove that proceedings for infringement of the opposed patent have been instituted against them or that the patent proprietor has requested them to cease alleged infringement of the patent and that they have instituted proceedings for a court ruling that they are not infringing the patent may, after the opposition period has expired, intervene in the opposition proceedings. If the notice of intervention is filed in good time and in due form, the intervention is to be treated as an opposition (see D‑IV, 5.6). For accelerated processing of oppositions on request, see D‑VII, 1.2 and E‑VIII, 5.