DANSP41800 - Notices of decisions: How to serve a notice of decision
Regulation 4 of the Social Security Contributions (Decisions and Appeals) Regulations 1999 (SI 1999 no 1027)
A notice of decision must be served by post. You cannot serve the notice by any other means of communication, for example, e-mail or fax.
Serving by post can include delivery by hand if this is ever considered necessary.
See DANSP28000 for general principles about issuing a notice of decision.