These Regulations make provisions implementing Council Directive 2018/822 which amends Council Directive 2011/16/EU (“the DAC”) on administrative cooperation in the field of taxation and repealing Directive 77/799/EEC and requires persons to report information in relation to certain types of arrangements known as reportable cross-border arrangements (defined in the DAC) to HMRC.
Local copy of SI

https://beta.parliament.uk/statutory-instruments/OGTRLwpj