A Suspicious Activity Report (SAR) is how the regulated sector flags potential money laundering or terrorist financing to the National Crime Agency (NCA). Knowing when you’re required to file — and what you must never do afterwards — is one of the most legally sensitive parts of AML compliance.

When to report

You must submit a SAR if, during the course of your business, you know or suspect (or have reasonable grounds to know or suspect) that a person is engaged in money laundering. This is a legal duty, not a judgement call about whether to involve the authorities — failing to report when the threshold is met is itself an offence under POCA 2002.

How to submit to the NCA

SARs are submitted to the NCA’s UK Financial Intelligence Unit, normally through the SAR Online portal. The NCA processes over 900,000 SARs every year — reporting suspicion is a routine, well-established part of operating in the regulated sector, not an exceptional escalation. Your business should have a nominated officer (see below) responsible for reviewing internal disclosures and deciding whether external submission to the NCA is required.

The MLRO / nominated officer role

Every regulated business must appoint a Money Laundering Reporting Officer (MLRO), sometimes called a nominated officer. Staff who suspect money laundering report internally to the MLRO, who then assesses whether the suspicion meets the threshold for an external SAR. This internal step doesn’t dilute the underlying legal duty — it ensures reports are properly assessed and consistently filed.

The tipping-off offence

Once a SAR has been made, or you know or suspect an investigation is underway, telling the customer — or anyone else — in a way that’s likely to prejudice that investigation is a separate criminal offence under POCA 2002, known as tipping off. This applies even to well-intentioned disclosures, such as warning a long-standing client “as a courtesy.” The safest approach is to say nothing about a report, ever, to anyone outside your reporting chain.