http://www.legislation.gov.uk/eur/2018/1861/article/24Regulation (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 V <Strong>ALERTS FOR REFUSAL OF ENTRY AND STAY ON THIRD-COUNTRY NATIONALS</Strong> Conditions for entering alerts for refusal of entry and stay Article 24 1 Member States shall enter an alert for refusal of entry and stay when one of the following conditions is met: a the Member State has concluded, based on an individual assessment which includes an assessment of the personal circumstances of the third-country national concerned and the consequences of refusing him or her entry and stay, that the presence of that third-country national on its territory poses a threat to public policy, to public security or to national security, and the Member State has consequently adopted a judicial or administrative decision in accordance with its national law to refuse entry and stay and issued a national alert for refusal of entry and stay; or b the Member State has issued an entry ban in accordance with procedures respecting Directive 2008/115/EC in respect of a third-country national. 2 The situations covered by point (a) of paragraph 1 shall arise where: a a third-country national has been convicted in a Member State of an offence carrying a penalty involving the deprivation of liberty of at least one year; b there are serious grounds for believing that a third-country national has committed a serious criminal offence, including a terrorist offence, or there are clear indications of his or her intention to commit such an offence in the territory of a Member State; or c a third-country national has circumvented or attempted to circumvent Union or national law on entry into and stay on the territory of the Member States. 3 The issuing Member State shall ensure that the alert takes effect in SIS as soon as the third-country national concerned has left the territory of the Member States or as soon as possible where the issuing Member State has obtained clear indications that the third-country national has left the territory of the Member States, in order to prevent the re-entry of that third-country national. 4 Persons in respect of whom a decision for refusal of entry and stay is taken as referred in paragraph 1 shall have the right to appeal. Such appeals shall be conducted in accordance with Union and national law, which shall provide for an effective remedy to be requested before a court.