HMRC have published a tax information and impact note about the UK’s implementation of the OECD’s model mandatory disclosure rules for CRS avoidance arrangements and opaque offshore structures.
On 17 January 2023 the International Tax Enforcement (Disclosable Arrangements) Regulations 2023 were laid before the House of Commons – see https://claritaxnews.com/international/si-2023-38-the-international-tax-enforcement-disclosable-arrangements-regulations-2023/. These regulations implement the mandatory disclosure rules. The regulations come into force on 28 March 2023.
https://www.gov.uk/government/publications/mandatory-disclosure-rules