http://www.legislation.gov.uk/eur/2009/987/article/21/2018-01-01Regulation (EC) No 987/2009 of the European Parliament and of the Council of 16 September 2009 laying down the procedure for implementing Regulation (EC) No 883/2004 on the coordination of social security systems (Text with relevance for the EEA and for Switzerland)Regulation (EC) No 987/2009 of the European Parliament and of the CouncilRegulation (EC) No 987/2009 of the European Parliament and of the Council of 16 September 2009 laying down the procedure for implementing Regulation (EC) No 883/2004 on the coordination of social security systems (Text with relevance for the EEA and for Switzerland)King's Printer of Acts of Parliamenthttps://webarchive.nationalarchives.gov.uk/eu-exit/https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02009R0987-20180101texttext/xmlen2025-04-162018-01-01 TITLE IIDETERMINATION OF THE LEGISLATION APPLICABLEObligations of the employer Article 21 1 An employer who has his registered office or place of business outside the competent Member State shall fulfil all the obligations laid down by the legislation applicable to his employees, notably the obligation to pay the contributions provided for by that legislation, as if he had his registered office or place of business in the competent Member State. 2 An employer who does not have a place of business in the Member State whose legislation is applicable and the employee may agree that the latter may fulfil the employer’s obligations on its behalf as regards the payment of contributions without prejudice to the employer’s underlying obligations. The employer shall send notice of such an arrangement to the competent institution of that Member State.