The complete guide to UK company due diligence in 2026

A friend of mine signed a six-figure supply contract last year on the strength of a clean Google search and a slick website. Eight weeks later the buyer dissolved and walked off with the stock. He had never opened Companies House.

That is what due diligence is supposed to prevent. Done properly, it takes minutes; skipped, it can take your year.

Whether you are onboarding a new client, signing a supplier, or buying a business, due diligence is what stands between you and an avoidable loss. UK fraud losses crossed £1.17bn in 2023 according to UK Finance, and a large share involves businesses that looked legitimate on paper.

This guide walks through a modern UK due diligence process — what to check, where to find it, and how to keep checking after the deal is signed.

What “due diligence” actually means in a UK context

Due diligence is the reasonable investigation a sensible business does before entering into a relationship. For regulated firms (accountants, solicitors, estate agents, crypto firms and many more) it is also a legal obligation under the Money Laundering Regulations 2017.

Even if you are not regulated, courts and insurers will ask what checks you ran. “We Googled them” is not a defence.

The 7 layers of a proper UK company check

1. Confirm the legal entity exists

Start with the company number (CRN) on Companies House. Match the registered name exactly — “Acme Ltd” and “Acme (UK) Ltd” are different companies. Check the status is Active, not dissolved, in liquidation, or proposed-to-strike-off.

2. Review the officers

Look at current directors and recent resignations. Multiple directors leaving in a short window is a classic warning sign. Cross-check directors against other companies they run — a pattern of dissolved or liquidated companies is a red flag.

3. Identify the Persons of Significant Control (PSCs)

PSCs are the people who really own or control the company — usually anyone holding more than 25% of shares or voting rights. “No PSC identified” on a trading company should make you pause.

4. Read the latest accounts

Even micro-entity accounts tell a story: net assets, cash, creditors, and whether the company is filing on time. Late filings or a sudden switch to dormant accounts deserve a question.

5. Check filings and charges

Outstanding charges show who has security over the company’s assets. A confirmation statement that has not been filed for a year usually means no-one is running the company properly.

6. Screen for sanctions and adverse media

Run the company and its directors against UK and global sanctions lists, PEP lists and negative news. This step is mandatory for regulated firms and just good practice for everyone else.

7. Verify trading reality

Does the website work? Does the address match? Are the VAT and bank details consistent? Many phoenix and invoice-fraud cases collapse at this final, human-judgement step.

From one-off check to ongoing monitoring

See our KYB explainer for the data points a defensible business check should contain, and our AML compliance guide for UK SMEs if you are a regulated firm. A company can change overnight. A new PSC, a winding-up petition or a sudden sanctions hit can appear days after you signed. The modern standard is continuous monitoring — daily or weekly re-checks on every key counterparty — with email alerts when something material changes. See why one-off supplier checks fail for the case for continuous monitoring, and how to spot a phoenix company before you give credit.

A checklist you can actually use

• Company number matches the legal entity on the contract
• Status: Active
• Confirmation statement and accounts up to date
• All current directors verified
• PSCs identified (or genuine reason for “none”)
• No undischarged charges that would block your transaction
• Sanctions, PEP and adverse media screening clear
• Address, website, VAT and bank details cross-checked
• Ongoing monitoring enabled

Don't guess. Check.

Every checklist item above is one tab on a CompanyCheckr report — status, officers, PSCs, charges, filings, sanctions and adverse news, scored and dated. Run a free check now, or sign up and add the counterparties you actually care about to ongoing monitoring.