SolvedCH117300 | Offshore matters: additional information: relevant dates for penalty reduction
From HM Revenue & Customs · Compliance Handbook
Schedule 21 FA 2016 came into force on 1 April 2017. The relevant date depends on the duty involved:
Inheritance Tax - in relation to transfers of value made on or after 1 April 2017.
Income Tax and Capital Gain Tax - in relation to tax years starting on or after 6 April 2017.
No changes to how penalties are calculated as a result of Schedule 21 FA 2016 should be made in relation to years that commence before 6 April 2017.