What is the relationship between a Unitary Patent and a European patent?

A Unitary Patent is a "European patent with unitary effect". The European patent is granted by the EPO according to the EPC. After grant and upon the proprietor’s successful request, unitary effect is attributed for the territory of the participating Member States.

The Unitary Patent system builds on the EPC. This means that the pre-grant phase is the same as for European patents that do not enjoy unitary effect. An applicant may file a European patent application at the EPO seeking the grant of a European patent for some or all of the EPC contracting states . The EPO examines the application in accordance with the EPC and, if all formal and substantive requirements for patentability are met, it grants a European patent.

Once a European patent has been granted, a separate, post grant procedure may be initiated at the EPO with a view to obtaining a Unitary Patent. If all the requirements are met, the EPO will register a Unitary Patent ("unitary effect") for that European patent.