How to switch accountants: a step-by-step guide for UK businesses

Switching accountants sounds harder than it is. There's a standard UK process, driven by professional ethics rules, that means your new firm handles most of the work. The whole thing usually takes 2 to 4 weeks.

Here's exactly what happens, and how to time it so nothing breaks.

The short version

1. Sign an engagement letter with your new accountant.
2. Write (or email) your old accountant to say you're moving.
3. Your new accountant writes to the old one asking for "professional clearance" and the handover pack.
4. The old accountant replies confirming there's no professional reason not to act, and sends the records.
5. Your new accountant registers as your agent with HMRC (and Companies House if you're a limited company).
6. You're moved.

You don't need a reason. You don't need permission. And your old accountant is professionally required to cooperate.

When to switch

The best time is immediately after your year-end filings are done. That way the old firm has closed the loop and there's a clean handover pack. In practice, most people switch when they're already frustrated, which is fine, just add a step to make sure nothing critical is mid-flight.

Times to avoid switching:

• Mid-Self Assessment season (November to late January). Your new firm won't be able to start until after 31 January.
• Two weeks before your VAT return is due. Wait until it's filed.
• Mid-audit or mid-HMRC enquiry. Finish the process with the current firm, then switch.

Step 1: Choose the new accountant

Basics:

• Fixed monthly fee, not hourly billing. Predictable is better.
• Cloud accounting (Xero, QuickBooks, FreeAgent) as the default, not Sage Desktop or paper.
• MTD-ready for VAT and (from April 2026) Income Tax.
• Response time in the engagement letter, not "we aim to reply promptly".
• A named person you actually speak to, not a shared inbox.

Have an intro call. Ask about their process, their software, and what happens when things go wrong. If they can't answer clearly, keep looking.

Step 2: Sign the engagement letter and let them do the work

Once you've signed with your new firm, they take over the process. You do three small things:

1. Send a short "goodbye" email to the old accountant, saying you're moving and giving permission for them to release your records. One line is enough:

"I'm moving my accounts to [new firm]. Please release my records and cooperate with their professional clearance request. Thanks for your work over the last [X] years."

2. Settle any outstanding fees with the old firm. If you don't, they have a professional right to hold onto your records (called a "lien") until they're paid. This is the single biggest cause of switch delays.

3. Give the new firm access to your accounting software. On Xero/QuickBooks/FreeAgent this means adding them as an adviser and, once they've confirmed setup, removing the old firm.

Step 3: What the new accountant handles

Behind the scenes, your new firm will:

• Write to the old firm for professional clearance (asking if there's any professional or ethical reason they shouldn't act).
• Request the handover pack: last set of accounts, tax return copies, working papers, tax reference numbers, capital allowance schedules, opening balances.
• Register as your agent with HMRC for Self Assessment, corporation tax, PAYE, and VAT as relevant.
• Register as your presenter at Companies House if you're a limited company.
• AML checks on you and the business (proof of ID, proof of address).
• Set up the software, connect bank feeds, and check the opening balances match the old firm's closing balances.

You'll be asked for a copy of your passport or driving licence, a proof of address (utility bill / bank statement from the last 3 months), and possibly a UTR or company number.

Step 4: What the old accountant must do

Under the ICAEW / ACCA / CIOT ethics rules, your old accountant must:

• Reply to the professional clearance letter within a reasonable time (typically 2-3 weeks).
• Disclose any professional matters the new firm should know (unpaid tax, active enquiries, missing filings).
• Release your records including trial balances, working papers, and copies of returns.
• Not obstruct the switch or contact HMRC to try to hold on to you.

They can decline to release records if fees are unpaid.

They cannot refuse simply because they don't want to lose you.

If the old firm drags their feet beyond about 4 weeks, your new accountant can escalate to their professional body. This is rare.

Common mistakes

• Switching mid-year without settling fees. The lien on your records will delay everything.
• Cancelling the old firm's software access before the new firm has confirmed setup. Do it in that order.
• Assuming HMRC will move automatically. They won't. Your new firm must submit a 64-8 authorisation for each tax head (Self Assessment, corporation tax, VAT, PAYE). Each takes 5-15 working days to activate.
• Filing something yourself in the gap. If a return falls due mid-switch, make sure someone is definitely handling it. Confirm in writing which firm is filing what.

Timing: what a typical switch looks like

• Week 1: sign engagement letter, send goodbye email, settle old fees, share software access.
• Week 2: new firm sends clearance letter, submits 64-8s to HMRC.
• Week 3: old firm replies with handover pack. New firm reviews opening balances.
• Week 4: HMRC activates the agent authorisations. You are fully moved.

If your accountant tells you it will take three months, it shouldn't.

Working with us

We onboard new clients this way regularly and handle the whole handover. If you'd like to move, get in touch and we'll take it from there.