The Official Journal of the European Union on 31 December 2020 publishes Commission Implementing Regulation (EU) 2020/2254 of 29 December 2020 on the making out of statements on origin on the basis of supplier’s declarations for preferential exports to the United Kingdom during a transitory period.
According to this Regulation, applying from 1st January 2021, "an exporter may until 31 December 2021 make out statements on origin for exports to the United Kingdom on the basis of supplier’s declarations to be provided by the supplier subsequently on condition that by 1 January 2022 the exporter has the supplier’s declarations in his or her possession.
If the exporter does not have those supplier’s declarations in his or her possession by that date, the exporter shall inform the importer on 31 January 2022 at the latest."