Article 4 - Signature and Entry into Force

1. This Protocol shall be open for signature by the member States of the Council of Europe and the other States signatory to the Convention. It shall be subject to ratification, acceptance or approval. A signatory may not ratify, accept or approve this Protocol unless it has previously or simultaneously ratified, accepted or approved the Convention. Instruments of ratification, acceptance or approval shall be deposited with the Secretary General of the Council of Europe.

2. This Protocol shall enter into force on the first day of the month following the expiration of a period of three months after the deposit of the third instrument of ratification, acceptance or approval.

3. In respect of any signatory State which subsequently deposits its instrument of ratification, acceptance or approval, the Protocol shall enter into force on the first day of the month following the expiration of a period of three months after the date of deposit.