How to Switch Accountants in the UK Without the Drama

Switching accountants is quicker and cheaper than most people think — usually 7 to 14 days end to end, done entirely by the new firm. This guide walks through every step.

Illustration of two folders changing hands representing switching accountants in the UK

Most people put off changing accountants for far longer than they should. The usual reason is not loyalty — it is the fear that it will be complicated, expensive, or that something will fall through the cracks mid-way. In practice, switching accountants takes seven to fourteen days, costs nothing, and the new firm does almost all of the work.

Why people switch

The patterns are consistent. The current accountant stopped replying. The bill went up and nobody warned anyone. The firm missed a deadline, or filed something wrong and never admitted it. The practice got bought by a larger group and the personal relationship vanished. Fees are hourly, so every email costs money. Or — the quiet one — the business grew and the accountant did not grow with it.

None of these are reasons to tolerate the situation for another year. A firm you cannot speak to honestly about your own numbers is not giving you what you are paying for.

What the switch actually looks like

Here is the real timeline most clients experience:

Day 1 — You sign an engagement letter with the new firm and give them permission to contact the old one.
Days 1-3 — The new firm sends a professional clearance letter to the old accountant, formally asking whether there is any professional reason not to accept the engagement, and requesting the relevant records.
Days 3-10 — The old firm responds (they are required to within a reasonable period). They send over the last filed accounts, the trial balance, your Companies House authentication code if they hold it, any payroll data, and VAT records.
Days 7-14 — The new firm files 64-8 agent authorisation forms with HMRC for every tax type that applies. HMRC posts you a code; you give it to the new firm; the authorisations go live.
From day 14 — The new firm is now your authorised agent for everything, holding every record, with nothing lost.

What you have to do

Four things, all of them small:

Email your current accountant to say you are moving on. Written notice protects you if there is a dispute about fees or deadlines later. A single polite sentence is enough.
Settle any outstanding invoice. Professional bodies allow the old firm to hold records against unpaid fees, so this clears the only legitimate obstacle to a quick handover.
Sign the engagement letter with the new firm.
When HMRC posts a 64-8 authorisation code, open it and forward the code to the new firm. That is the only time you have to do anything administrative.

When is the right time to switch?

Any time, with two sensible exceptions.

If a filing deadline is less than three weeks away and your current firm is already preparing the return, let them finish — then switch for the next period. Rushing a handover in the final days before a deadline helps nobody.

If you are mid-year end audit, finish the audit. Switching during an audit creates records reconciliation headaches that are not worth the few months saved.

Otherwise, there is no bad time. The idea that you have to wait until your year end is a myth spread by firms that do not want you to leave.

What to look for in a new firm

Three things that separate a good practice from an average one:

Fixed, agreed fees. You should know in advance what every month will cost. An hourly billing model punishes you for asking questions, which is the exact opposite of what an accountant is for.

A named person. You should know who is doing your work, not just "the team". Named accountability means someone cares when you call.

A response-time commitment. "We reply within one working day" is a measurable promise. "We will get back to you when we can" is not.

Getting help with this

AJH Accountants handles fixed-fee accounting across every service you need for clients across the UK. We file the return, tell you what you can claim, and deal with HMRC on your behalf, so nothing depends on you remembering a deadline.

See how our fixed-fee accounting across every service you need service works, or send us a quotation request and we will call you back. You can also call the office on 01204 840303.

Originally published at ajhaccountant.co.uk/blog/how-to-switch-accountants-uk-2026.