After the transition period ends the EU REACH Regulation will be brought into UK law under the European Union (Withdrawal) Act 2018. REACH, and related legislation, will be replicated in the UK with the necessary changes to make it operable in a domestic context. The key principles of the EU REACH Regulation will be retained.

The domestic regime that will operate in the UK from 1 January 2021, will be known as UK REACH. The REACH Statutory Instrument can be found on legislation.gov.uk and will make its way through the parliamentary processes, with the intention that it will come into force at the end of the transition period.

In short, if you have registered under EU REACH you will have to register under UK REACH and if you imported from an EU source registered under REACH you may now have to register under UK REACH as the importer!