What is money laundering? The stages, the law, and why it matters

Money laundering is the process of making the proceeds of crime look legitimate. The aim is simple: let a criminal hold, move and spend illicit money without the wealth itself betraying where it came from. Almost every profit-driven crime — fraud, drug trafficking, corruption, tax evasion — generates funds that, at some point, need to be cleaned.

For anyone doing business with companies, charities or individuals, money laundering is not an abstract problem. It is the reason due-diligence rules exist, the reason banks ask where your money came from, and the reason a single bad counterparty can expose you to criminal liability. This guide explains how laundering works and what the UK law actually says.

1The three stages: placement, layering, integration

Practitioners and regulators describe money laundering using a three-stage model. Not every scheme has all three stages, and they often overlap, but the model is the standard way to think about how dirty money is cleaned.

Placement is getting the illicit funds into the financial system. Cash is the hardest proceed to use and the easiest to trace to a crime, so the launderer's first problem is converting it into something more flexible — bank deposits, casino chips, money orders, prepaid cards. To avoid scrutiny, large sums are often broken into many smaller amounts (sometimes called "smurfing" or "structuring").

Layering is the deliberate creation of distance between the money and its source. Funds are moved through a chain of transactions — between accounts, across borders, in and out of shell companies, converted to and from assets — each step making the audit trail longer and harder to follow. The complexity is the point.

Integration is the return of the now-laundered money to the criminal as apparently legitimate wealth: a property purchase, a business investment, a luxury asset, a loan repaid to oneself. By this stage the funds look like the proceeds of ordinary economic activity.

The Financial Action Task Force (FATF), the inter-governmental body that sets the global anti-money-laundering standards, frames the whole exercise around denying criminals the ability to enjoy and reuse their proceeds. Disrupting any stage — but especially placement and layering — is what AML controls are designed to do.

2What the UK law actually says

In the UK, the principal money laundering offences are in Part 7 of the Proceeds of Crime Act 2002 (POCA). There are three:

• Section 327 — concealing. Concealing, disguising, converting, transferring, or removing criminal property.
• Section 328 — arrangements. Entering into or becoming concerned in an arrangement that you know or suspect facilitates the acquisition, retention, use or control of criminal property by or on behalf of another person.
• Section 329 — acquisition, use and possession. Acquiring, using or possessing criminal property.

Each of these is triable either way and carries a maximum penalty of 14 years' imprisonment, a fine, or both, as set out in the Crown Prosecution Service's prosecution guidance.

a"Criminal property" — and the low bar of suspicion

The offences turn on the concept of criminal property. Under section 340 of POCA, property is criminal property if it constitutes or represents a person's benefit from criminal conduct and the alleged offender knows or suspects that it does.

Two things make this broad. First, "property" includes money, real estate and intangible property of all kinds. Second, the mental threshold is knowledge or suspicion — you do not have to be certain the money is dirty to commit an offence by dealing with it. That low bar is precisely why regulated firms are so cautious, and why "I wasn't sure, so I proceeded anyway" is not a safe position.

bReporting offences in the regulated sector

POCA also creates offences that apply specifically to people working in the regulated sector (banks, accountants, lawyers, estate agents and others):

• Section 330 — failure to disclose. A regulated-sector employee who knows or suspects (or has reasonable grounds to) that another person is laundering, and fails to make the required disclosure, commits an offence carrying up to 5 years' imprisonment.
• Section 333A — tipping off. Disclosing information that is likely to prejudice a money-laundering investigation, where the information came to you in the course of regulated-sector business, carries up to 2 years' imprisonment.

These provisions are why a bank cannot simply tell a customer "we've filed a report about you," and why suspicious activity reporting is a legal duty, not a courtesy.

3How big is the problem?

Money laundering is, by design, hidden, so precise figures are impossible. What is not in doubt is scale: the UK government and law-enforcement bodies have repeatedly described the laundering of criminal proceeds through and within the UK as running into the tens of billions of pounds a year, and the Sentencing Council's money laundering guideline treats the most serious offences as warranting substantial custodial sentences. The harm is not only financial: laundering is what makes serious and organised crime profitable in the first place.

4Why this matters for due diligence

Every anti-money-laundering control — identity checks, sanctions and PEP screening, source-of-funds questions, ongoing monitoring — exists to interrupt one of the three stages or to satisfy the legal duties POCA imposes. If you understand the offences, the rest of the AML world makes sense:

• You screen counterparties because dealing with criminal property, even unknowingly-but-suspiciously, is an offence.
• You document who you dealt with and why because the regulated sector must be able to show it managed the risk.
• You ask awkward questions about source of wealth because integration depends on no one asking them.

The next guides in this series cover the UK rulebook that sits on top of POCA — the Money Laundering Regulations 2017 — and the specific checks they require.