Please see the following trade agreement updates from BEIS.
UK – Japan Trade Agreement reached in principle: https://www.gov.uk/government/news/uk-and-japan-agree-historic-free-trade-agreement
Other updates on UK-EU negotiations and Customs:
Meeting of the Withdrawal Agreement Joint Committee on 10 September: The UK Government hosted a meeting of the Withdrawal Agreement Joint Committee on 10 September in London.
Customs, VAT and Excise UK Transition legislation from 1 January 2021: EU Exit legislation, regulations and notices for Customs procedures applicable to UK Transition.
Draft notices to be made under The Customs (Bulk Customs Declaration and Miscellaneous Amendments) (EU Exit) Regulations 2020: Find draft text for notices which have force of law under Customs Regulations.