# Regulation (EU) No 1257/2012 of the European Parliament and of the Council of 17 December 2012 implementing enhanced cooperation in the area of the creation of unitary patent protection, Article 4: Date of effect

Extent: E+W+S+N.I.

1. A European patent with unitary effect shall take effect in the participating Member States on the date of publication by the EPO of the mention of the grant of the European patent in the European Patent Bulletin.
2. The participating Member States shall take the necessary measures to ensure that, where the unitary effect of a European patent has been registered and extends to their territory, that European patent is deemed not to have taken effect as a national patent in their territory on the date of publication of the mention of the grant in the European Patent Bulletin.

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Source: https://www.legislation.gov.uk/eur/2012/1257/article/4 (the official version)
Page: https://openlegislation.uk/eu-regulation-2012-1257/article-4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.