If you run a UK accountancy firm that files on behalf of corporate clients, you almost certainly need to register as an Authorised Corporate Service Provider before the Economic Crime and Corporate Transparency Act regime hits its 18 November 2026 cliff. Most partners we speak to are roughly aware of this. Most are not yet ready.

This is the working checklist we hand to firms who are starting from zero. It’s deliberately practical — there are no inspirational quotes, and we’ve stripped out the parts where the official guidance asks you to confirm something you already know.

Before you start

Three things to have on hand:

  • Your firm’s AML supervisor (ICAEW, ACCA, AAT, CIOT, IFA, or HMRC). You’ll be referencing this body throughout.
  • Your firm’s money-laundering reporting officer (MLRO) name, role, and contact details.
  • A list of every partner, director, or controlling individual who will need to be identity-verified as part of the application.

If your AML supervisor is HMRC, allow longer than the official guidance suggests. The HMRC AML registration queue has been moving slowly through 2025–26, and that delay flows through into ACSP eligibility.

Step 1 — Confirm AML supervision is current

Your ACSP application will be rejected if your AML supervision is lapsed, suspended, or under review. Before you touch the Companies House form:

  1. Check your last AML supervision renewal date.
  2. Check that all relevant individuals at your firm are on your supervisor’s MLRO/responsible-person register.
  3. Resolve any outstanding fee, document, or fitness-and-properness queries.

If anything is unclear, contact your supervisor before you submit. Companies House cross-checks; their failure mode is “rejection without explanation.”

Step 2 — Identity-verify the responsible individuals

This is the step most firms underestimate.

Every individual who has authority to act under the ACSP — not just the partners, but anyone who could file or instruct a filing — needs a verified Companies House identity. That means a GOV.UK One Login identity, not just an “email and password.”

A few things that matter:

  • The verification can be done direct via GOV.UK One Login, or through a registered ACSP. (Yes, even before you are an ACSP, you can use another ACSP to verify your team. This includes Endorser, once you’re a customer.)
  • Verification is biometric. The individual needs a phone, a valid passport or driving licence, and roughly five minutes.
  • Each verification produces a Companies House identity reference. Keep these. You’ll need them.

Endorser’s verification flow runs the GOV.UK-aligned IDV journey on the individual’s phone, returns the identity reference into the firm’s record, and writes the result into the audit log. You’ll also use that same flow for every corporate-client director and PSC after registration.

Step 3 — Gather your supporting documents

Companies House will ask for, broadly:

  • Proof of AML supervision (most recent renewal letter or supervisor portal screenshot).
  • Evidence of professional indemnity insurance.
  • A description of the corporate services you offer.
  • Identity references for all responsible individuals (from Step 2).
  • A copy of your firm’s current AML policies and procedures.

We’ve seen firms attempt the form with a 2018 AML policy. The supervisor wants the policy to reflect the current Money Laundering Regulations (the 2017 regulations as amended in 2022 and 2024). If yours doesn’t, fix that first.

Step 4 — Submit and pay

The application fee is currently £59 (correct as of April 2026 — confirm at submission time). The form is on the Companies House service portal; access it via the firm’s GOV.UK One Login account.

After submission:

  • You’ll receive an acknowledgement within 24 hours.
  • Decisions typically issue within 10 working days, but allow 25 if your supervisor is HMRC.
  • If your application is rejected, the rejection reason is usually vague. Contact the Companies House ACSP team within 14 days to resubmit.

Step 5 — Operationalise the workflow

This is where firms most often stall — and the reason Endorser exists.

Once you’re registered, every filing on behalf of a client triggers the requirement to verify the relevant individual. By the November 2026 cliff, you’ll need to have verified every director, every PSC, and every LLP member of every corporate client you file for. For a firm with 400 corporate clients, that’s typically around 1,000 verifications.

You need:

  • A system of record that tracks which client owes which verification.
  • A bulk send mechanism so you’re not emailing one person at a time.
  • An evidence pack export so you can survive an AML supervisor inspection.
  • A fee model so the verification cost gets passed through to clients with margin.

A spreadsheet does none of these. Endorser does all four.

A note on timing

We’ve watched a lot of firms wait until late summer 2026 to start registering. That’s a mistake. The Companies House queue lengthens monotonically as the deadline approaches, and so does your supervisor’s. Register in Q2 2026, get your team’s identities verified in Q3, and use Q4 for the bulk client work. That’s the sequence that ships clean.

If you’ve read this far and want to see what the operational side looks like, book a demo. Fifteen minutes, your real client list, no pitch deck.