Since the beginning of 2021 the UK’s new post-Brexit regime for regulating use of chemicals, "UK REACH", has been in operation. A key part of UK REACH is the creation of a new database of chemical risk information. Such a database is critical for effective chemical regulation. Current UK REACH proposals involve populating a UK database from scratch. As this system will likely need to contain millions of pages of risk-relevant data, it will be very expensive to build. As a result, there is pressure to reduce costs. As scientists working in chemical risk assessment and related areas, we have asked the UK Government to resist proposals to reduce costs by lowering requirements for chemical safety data in UK REACH, and instead explore securing UK access to the EU REACH chemicals safety database. Our arguments for this are in this letter that was sent to UK Ministers on Friday 30 April 2021.