
Article 1 
For the purposes of this Regulation, the definitions laid down in Article 1 of Regulation (EC) No 883/2004 and Article 1 of Regulation (EC) No 987/2009 apply.
Article 2 
This Regulation applies to the following persons:

((a)) nationals of a Member State, stateless persons and refugees who are or have been subject to the legislation of one or more Member States and who are or have been in a situation involving the United Kingdom before the date of application of this Regulation, as well as members of their families and survivors;
((b)) nationals of the United Kingdom who are or have been subject to the legislation of one or more Member States before the date of application of this Regulation, as well as members of their families and survivors.
Article 3 
This Regulation applies to all branches of social security provided for in Article 3 of Regulation (EC) No 883/2004.
Article 4 
The principle of equality of treatment as laid down in Article 4 of Regulation (EC) No 883/2004 shall apply to the persons referred to in Article 2 of this Regulation as regards any situation that has occurred before the date of application of this Regulation.
Article 5 

1. The principle of assimilation as laid down in Article 5 of Regulation (EC) No 883/2004 shall apply as regards benefits or income acquired and facts or events that have occurred in the United Kingdom before the date of application of this Regulation.
2. The principle of aggregation as laid down in Article 6 of Regulation (EC) No 883/2004 shall apply as regards periods of insurance, employment, self-employment or residence in the United Kingdom that were completed before the date of application of this Regulation.
3. Any other provisions of Regulation (EC) No 883/2004 and Regulation (EC) No 987/2009 necessary to give effect to the principles laid down under paragraphs 1 and 2 of this Article shall apply.
Article 6 

1. This Regulation shall be without prejudice to the existing social security conventions and agreements between the United Kingdom and one or more Member States which are in compliance with Article 8 of Regulation (EC) No 883/2004 and Article 9 of Regulation (EC) No 987/2009.
2. This Regulation shall be without prejudice to social security conventions and agreements between the United Kingdom and one or more Member States concluded after the day on which the Treaties cease to apply to the United Kingdom pursuant to Article 50(3) TEU and that cover the period before the date of application of this Regulation, provided that those conventions and agreements give effect to the principles laid down in Article 5(1) and (2) of this Regulation, apply the provisions referred to in Article 5(3) of this Regulation, are based on the principles of Regulation (EC) No 883/2004, and are in keeping with the spirit thereof.
Article 7 
One year after the date of application of this Regulation, the Commission shall submit a report to the European Parliament and to the Council on the implementation of this Regulation. That report shall address, in particular, practical problems arising for the persons concerned, including those arising from the lack of continuity of the coordination of social security systems.
Article 8 
This Regulation shall enter into force on the day following that of its publication in the Official Journal of the European Union.
It shall apply from the day following that on which the Treaties cease to apply to the United Kingdom pursuant to Article 50(3) TEU.
However, this Regulation shall not apply if a withdrawal agreement concluded with the United Kingdom in accordance with Article 50(2) TEU has entered into force by the date of application of this Regulation.
This Regulation shall be binding in its entirety and directly applicable in all Member States.Done at Strasbourg, 25 March 2019.
For the European Parliament
The President
A. TAJANI
For the Council
The President
G. CIAMBA