Client identity verification for Companies House: what advisors need to know

If your firm files or advises on behalf of clients, ECCTA gives you a second role beyond your own compliance: you can verify your clients' identity for them, as an Authorised Corporate Service Provider (ACSP). Here is what that role involves and what it requires of your firm.

What is client identity verification for Companies House?

It is the process by which an Authorised Corporate Service Provider (ACSP) - typically an accountant, solicitor, or company formation agent - verifies a client's identity on Companies House's behalf, as an alternative to the client verifying themselves directly through GOV.UK One Login. It saves the client a separate step and lets the firm confirm the check was actually done, rather than taking a client's word for it.

Who needs to become an ACSP to verify clients?

Any firm that wants to verify directors or PSCs on behalf of clients, or file for them under the new rules, must register as an ACSP with Companies House - which requires being supervised for anti-money-laundering purposes, typically by a recognised accountancy or legal body. Sole practitioners and firms already registered for AML supervision are generally best placed to apply - the ACSP status is separate from, but sits alongside, that existing supervision.

What does the verification process actually involve?

The ACSP confirms the client's identity to the same standard as GOV.UK One Login - checking photo ID and proof of address, in line with the firm's existing AML/CDD obligations - then submits confirmation to Companies House, which issues the client an ACSP reference number to use on future filings. Most firms already run an equivalent check as part of client onboarding for AML purposes, so ACSP verification is often a formalisation of an existing process rather than new work from scratch.

What happens if you file for a client whose identity you haven't verified?

The filing risks rejection if the client has not verified through any route, and from 18 November 2026 knowingly submitting on behalf of an unverified director carries compliance risk for the firm as well as the client. See our guide on what an unverified director status means for the consequences on the client's side, including the blocked confirmation statement that already applies today.

How do you track verification across a whole client book?

One client at a time does not scale once you are responsible for dozens or hundreds of companies - Registrum's free portfolio scan checks a full client list in one pass and ranks the gaps by confirmation statement date. Our guide for accountants managing a client book covers building that list, and our guide to checking verification status covers reading the result once you have it.

Send us your client list and get back a gap report showing exactly who still needs verifying, ranked by confirmation statement date, so you know where ACSP verification is most urgent.