The Regulations amend the Corporation Tax (Instalment Payments) Regulations 1998 (S.I. 1998/3175) (“the Principal Regulations”) to provide for new instalment dates in respect of very large companies and related matters. By regulation 1(2), the Regulations have effect in relation to accounting periods beginning on or after 1st April 2019.
Link: The Corporation Tax (Instalment Payments) (Amendment) Regulations 2017
Source: Legislation .gov.uk