Class 1 NICs: reporting NICs in RTI: what is an RTI employer?
Social Security (Contributions) Regulations 2001, Schedule 4, Para 1
An “employer” is the secondary contributor, determined by legislation (see NIM11516).
From 6 October 2013, all employers with NICs liability are RTI employers and should report NICs data in real time.
An employer who needs to report NICs through RTI should register as an employer with HMRC through normal channels.
See also paper filers, NIM11565.