http://www.legislation.gov.uk/eur/2018/1861/article/39Regulation (EU) 2018/1861 of the European Parliament and of the Council of 28 November 2018 on the establishment, operation and use of the Schengen Information System (SIS) in the field of border checks, and amending the Convention implementing the Schengen Agreement, and amending and repealing Regulation (EC) No 1987/2006Regulation (EU) 2018/1861 of the European Parliament and of the CouncilRegulation (EU) 2018/1861 of the European Parliament and of the Council of 28 November 2018 on the establishment, operation and use of the Schengen Information System (SIS) in the field of border checks, and amending the Convention implementing the Schengen Agreement, and amending and repealing Regulation (EC) No 1987/20062020-12-10King's Printer of Acts of Parliamenthttps://webarchive.nationalarchives.gov.uk/eu-exit/https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02018R1861-20190611texttext/xmlen2019-06-11 CHAPTER VII <Strong>RIGHT OF ACCESS AND REVIEW AND DELETION OF ALERTS</Strong> Review period for alerts Article 39 1 Alerts shall be kept only for the time required to achieve the purposes for which they were entered. 2 An issuing Member State shall, within three years of the entry of an alert into SIS, review the need to retain it. However, if the national decision on which the alert is based provides for a longer period of validity than three years, the alert shall be reviewed within five years. 3 Each Member State shall, where appropriate, set shorter review periods in accordance with its national law. 4 Within the review period, the issuing Member State may, following a comprehensive individual assessment, which shall be recorded, decide to retain the alert for longer than the review period, where this proves necessary and proportionate for the purposes for which the alert was entered. In such a case, paragraph 2 shall also apply to the extension. Any such extension shall be communicated to CS-SIS. 5 Alerts shall be deleted automatically after the review period referred to in paragraph 2 has expired except where the issuing Member State has informed CS-SIS of an extension pursuant to paragraph 4. CS-SIS shall automatically inform the issuing Member State of the scheduled deletion of data four months in advance. 6 Member States shall keep statistics on the number of alerts the retention periods of which have been extended in accordance with paragraph 4 of this Article and transmit them, upon request, to the supervisory authorities referred to in Article 55. 7 As soon as it becomes clear to a SIRENE Bureau that an alert has achieved its purpose and should therefore be deleted, it shall immediately notify the authority which created the alert. The authority shall have 15 calendar days from the receipt of that notification to reply that the alert has been or shall be deleted or shall state reasons for the retention of the alert. If no reply has been received by the end of the 15-day period, the SIRENE Bureau shall ensure that the alert is deleted. Where permissible under national law, the alert shall be deleted by the SIRENE Bureau. SIRENE Bureaux shall report any recurring issues they encounter when acting under this paragraph to their supervisory authority.