What to expect when you switch accountants (and how the process works)

Switching accountants is one of those things that sounds harder than it is. The process is standardised across the profession, governed by ICAEW and ACCA ethics rules, and typically takes two to four weeks from the day you decide to move to the day your new accountant is fully in place. This guide sets out exactly what happens, in what order, and what you need to do.

You do not need a reason

First, the thing nobody tells you: you do not need a reason to switch. You do not need to be unhappy. You do not need to justify the decision to your old accountant. Switching is a normal commercial choice, and every chartered accountant in the UK is bound by professional rules that require them to cooperate with a handover regardless of circumstances.

The most common triggers are:

Your current accountant is compliance-only and you want advisory
The service has become unresponsive or impersonal
Fees have crept up without a corresponding improvement in service
Your business has grown beyond your current accountant's capacity
Location or working style mismatch (postal handovers in 2026 are rarely a good fit for modern businesses)

Any of these is sufficient. None of them require negotiation with the outgoing firm.

The eight-step process

Here is what the process actually looks like, start to finish.

Step 1: Choose your new accountant and sign the engagement letter

Before anything else, you need to have formally engaged the new firm. This usually involves:

An initial conversation about your needs
A quote or proposal
A signed engagement letter setting out the scope of work and fees
Anti-money laundering (AML) identity verification (proof of ID and proof of address)

Nothing can start until this is done, because the new firm cannot request information from anyone else until you are their client.

Step 2: Notify your current accountant

You send a short, polite email to your current accountant saying you have decided to move, and giving the name of the new firm. You do not need to explain why. Template:

Dear [Name], I am writing to let you know that I have decided to move my accountancy services to [new firm name] with effect from [date]. Please cooperate with their request for professional clearance and the handover of my records. Thank you for your work over the past [period]. Best regards, [Your name]

That is the entire message. No justification, no defence, no explanation needed.

Step 3: Professional clearance letter

The new accountant writes to the old accountant to request "professional clearance". This is a standardised letter that asks two things:

Is there any professional reason why we should not accept this client?
Please provide handover information, including copies of the most recent accounts, tax returns, working papers, and any matters we need to be aware of.

Under the ICAEW Code of Ethics (and equivalent ACCA/CIOT rules), the old accountant must respond promptly. They cannot refuse to respond because of an outstanding fee dispute, unpaid invoice, or personal disagreement. They can mention these things in their reply, but they cannot withhold clearance because of them.

Response times vary. Professional accountants respond within two weeks. Some drag it out to four. A very small number try to stall beyond that, in which case the new accountant will escalate through professional channels.

Step 4: Handover of documents

The old accountant provides the new accountant with:

Last filed accounts (full and abbreviated)
Last filed Corporation Tax return (CT600) with computations
Last filed Self Assessment return(s)
Working papers supporting the last accounts (trial balance, schedules, reconciliations)
Fixed asset register
Any ongoing correspondence with HMRC
Copies of HMRC agent authorisations they hold

The handover is free. Your old accountant cannot charge you for handing over your own records. They can charge for additional specific work (for example, producing a custom reconciliation you never asked for before), but routine handover is included in the final bill for work already done.

Step 5: New HMRC agent authorisation

HMRC does not accept handovers of agent authorisation between firms. The new firm has to apply for fresh authorisation for each tax type you need covered. This is done via:

Digital handshake. The new accountant sends you an email, you click a link, log in to your Government Gateway account, and approve the authorisation. Applies to most services including VAT, Corporation Tax, Self Assessment, and PAYE.
Paper form 64-8. The older, slower route, still used for some services. Avoided where possible.

Once authorised, HMRC sends all future correspondence to the new agent's address. Your old accountant stops receiving your tax notices.

This step typically takes 1 to 5 working days for digital handshake, or 2 to 4 weeks for 64-8.

Step 6: Software handover

If you use cloud accounting software (Xero, QuickBooks, FreeAgent, Sage), your new accountant will be invited to the file as an adviser, and your old accountant will be removed. You keep the subscription. The data stays where it is. Nothing migrates.

If your old accountant was keeping your books in their own desktop software, they will provide a copy of the data file or (more commonly) a PDF trial balance and journals, which your new accountant will import into a cloud platform.

Step 7: Opening balances agreed

Before your new accountant can start producing accounts, they need to agree opening balances from the last filed accounts. This means reconciling what the old accountant filed with what sits in the books today, and correcting any discrepancies.

For most switches, this is straightforward and takes a few hours. For businesses whose records are messy or where the old accountant made adjustments the client never saw, it can take longer. This is why the fee for the first year with a new accountant is sometimes slightly higher than subsequent years.

Step 8: Notify Companies House of registered office change (if applicable)

If your old accountant provided a registered office address and you are moving to one your new accountant provides, file a form AD01 at Companies House (or it is filed digitally by your new accountant with your authority). Free and takes minutes.

What your old accountant finishes and what the new one picks up

The normal rule is that the old accountant finishes any work already started and billed for, and the new accountant picks up everything from the effective handover date.

Example: You switch on 15 May. Your old accountant has already started your 31 March year-end accounts and has billed for them. They finish those accounts. Your new accountant picks up from the next accounting period (the year starting 1 April) plus any open Self Assessment returns, VAT returns after the switch date, and all future year-ends.

Exceptions exist. If the old accountant refuses to finish work they have been paid for, or if they try to hold work hostage over a fee dispute, ICAEW has a complaints procedure. This is rare.

What you are responsible for during the switch

Four things the client needs to do:

Sign the engagement letter with the new firm and complete AML checks
Notify the old firm of the switch in writing (the short email above)
Approve HMRC agent authorisation requests promptly when they arrive
Pay any outstanding invoices with the old firm. Not strictly required for the switch itself, but advisable for a clean break.

That is it. You do not have to argue, negotiate, or do anything uncomfortable. The professional clearance and handover mechanics are handled between the two accountants.

Common concerns

"Will my old accountant be difficult?" Almost certainly not. Professional rules require cooperation. The overwhelming majority of UK accountants handle handovers routinely and professionally, even for clients they are sorry to lose.

"Will my tax be disrupted?" No. Your tax obligations do not change. Only who prepares the returns changes. All of your filings, payments, and HMRC interactions continue under the new firm.

"What if I'm mid-year for VAT or accounts?" No problem. The old firm completes any return they have started and billed for, and the new firm picks up the next one. For ongoing services like bookkeeping or payroll, you agree a clean cut-off date with both firms.

"Will I lose any historic data?" No. All your historic filings remain on record with HMRC and Companies House. Your new accountant can pull them directly from HMRC via agent services and from Companies House via the public register.

"What if I regret switching?" You can switch again. There is no lock-in. Most engagement letters allow either party to terminate with reasonable notice (typically 30 days).

What a well-run switch looks like

For most owner-managed businesses, a well-run switch follows this timeline:

Day 1: Engagement letter signed with new firm, AML completed
Day 2: Client notifies old firm in writing
Day 2–3: New firm sends professional clearance letter to old firm
Day 3–5: New firm sends HMRC agent authorisation requests (digital)
Day 5–7: Client approves HMRC authorisations via Government Gateway
Day 7–14: Old firm responds to clearance letter and sends handover documents
Day 14–21: New firm reviews handover, agrees opening balances, imports data into software
Day 21 onwards: New firm is in place and operational

Three weeks is a realistic target. Four weeks is normal if the old firm is slow to respond. Anything longer than six weeks is unusual and suggests the old firm is dragging.

The bottom line

Switching accountants is a standardised, low-friction process. You sign with the new firm, send a short email to the old firm, and the two accountants handle everything else. You need to approve HMRC authorisations and pay any final invoices. The switch typically completes in two to four weeks and does not disrupt your tax obligations or existing filings.

If you are thinking about moving your accounts to S&J, the first step is the quote generator. It takes two minutes and gives you a fixed price for your situation, with no obligation and no prospect call required unless you want one.