New UK requirements will introduce a unified regulatory regime for operational incident reporting and reporting of material third‑party arrangements (MTPAs) from 18 March 2027. The rules, which are designed to align as far as possible with international regimes, introduce aligned definitions, templates, and processes for notifying regulators of serious operational incidents above a defined threshold and for registering and notifying new or significantly changed MTPAs. We take a look at the aims of the new regime, highlight key points to note and discuss implementation considerations for firms.