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Can I switch accountants mid-year? When is the best time to switch?
Sources: gov.uk — authorise an agent; ICAEW / ACCA professional conduct rules.
Written by Mehmood Rajoka
Managing Partner, RR Accountants · IFA-supervised practice
Direct answer
Yes — you can switch accountants at any time of year. You do not have to wait until your year-end or the end of the tax year. The process is the same whenever you do it. Timing affects cost and convenience rather than whether you're allowed: the cleanest moment is usually just after a major filing (your year-end accounts, a Corporation Tax return, or a VAT quarter), because it creates a natural break in the work and avoids paying two firms for overlapping effort. But if you're unhappy now, waiting isn't necessary.
Timing comparison: when to switch
Three common windows, and what each one means for cost and convenience.
| Timing window | What it means | Cost / convenience |
|---|---|---|
| Just after a major filing | Year-end accounts done, CT return submitted, VAT quarter closed | Cleanest — no half-finished work |
| Mid-year-end process | Books in progress, draft accounts | Risk of paying both firms for overlapping work |
| Just before a deadline | A filing date is imminent | Factor in 1–2 weeks for HMRC agent authorisation codes |
Source: gov.uk — Authorise an agent to deal with HMRC and ICAEW/ACCA professional conduct guidance.
You can switch whenever you like
There is no rule — in tax law, in HMRC's processes, or in your engagement letter — that says you have to wait for the end of a tax year, the end of your company year-end, or any other date before you change accountant. If your current accountant is letting you down, you can start the process today.
The mechanics are identical whatever month of the year you begin. Your new accountant sends a professional clearance letter to your old firm, runs an AML/ID check on you, requests your records, and applies for agent authorisation with HMRC. None of that is gated on a calendar date.
The clean break window
The smoothest handover is right after a completed milestone — your year-end accounts have been filed at Companies House, your Corporation Tax return has been submitted to HMRC, or the end of a VAT quarter has just passed. At that point there is no half-finished work hanging between two firms.
For most owner-managed limited companies, that means the weeks immediately after your accounts and CT return are filed (typically 9–12 months after year-end) are the textbook cleanest moment. For VAT-registered businesses, the first week of a new VAT quarter is the equivalent natural break.
The overlap cost to avoid
If you switch in the middle of your year-end process — books partly reconciled, draft accounts in progress, payroll partway through the year — you might pay your old firm for the work done so far and your new firm to pick it up. There is usually some duplication: the new accountant has to review what's been done, verify the trial balance, and reconcile any open items.
In practice the overlap cost is usually a few hundred pounds rather than a few thousand — but it's the one practical reason advisers say "wait until year-end." Switching at a natural break avoids it entirely.
Deadlines: factor in HMRC authorisation time
The one operational constraint is HMRC's agent authorisation process. When your new accountant applies for authorisation as your agent, HMRC issues a code that arrives by post and can take a week or two to reach you. You then enter that code online to activate the authorisation. Until that's done, the new firm cannot file returns or speak to HMRC on your behalf.
That means if a filing deadline is close — a VAT return, a Self Assessment, a Corporation Tax return — you need either enough runway (two to three weeks before the deadline is comfortable), or you let the old firm complete that imminent filing and move afterwards.
See gov.uk — Authorise an agent to deal with HMRC for the current process. The old paper 64-8 still exists, but online authorisation is now the standard route.
The honest takeaway
"Wait until year-end" is advice about cost-efficiency, not permission.
If your relationship has broken down, or you're missing deadlines because of your current accountant, the cost of a little overlap is usually trivial next to the cost of staying. Don't let timing keep you somewhere that isn't working.
Switching mid-year — FAQs
Can I change accountant in the middle of the tax year?
Yes. There is no rule that requires you to wait for the end of the tax year, your company year-end, or any other date. You can begin the switch at any time. Your new accountant sends a professional clearance letter to your old firm, requests your records, and gets authorised with HMRC as your agent. The mechanics are identical whatever month you start.
When is the best time of year to switch accountant?
The cleanest moment is right after a major completed filing — your year-end accounts, a Corporation Tax return, or the end of a VAT quarter. At that point there is no half-finished work to split between two firms, so you avoid paying both for overlapping effort. That said, 'best' means cost-efficient, not 'allowed': if your current accountant is letting you down, the cost of a little overlap is usually trivial next to the cost of staying.
Will I pay two firms if I switch mid-year-end?
Potentially, yes — that is the main practical cost of switching mid-process. If your old firm has already done some of the year-end work, they will usually bill for what they have done; your new firm then picks up where they left off, which can mean a small duplication. The way to avoid this is to switch at a natural break: after the year-end is filed, after the CT return is submitted, or at the end of a VAT quarter.
How close to a deadline can I switch?
You can switch close to a deadline, but you have to factor in the time for HMRC to issue agent authorisation codes — these arrive by post and can take a week or two. With enough runway (two to three weeks before a critical filing), a switch is comfortable. If the deadline is days away, the safer route is to let your current accountant complete that filing, then switch immediately afterwards.
Should I wait until after my Self Assessment to switch?
Waiting until after the 31 January Self Assessment deadline is a reasonable choice if your current accountant is doing that return — it gives you a natural break point. But if they are missing deadlines, unresponsive, or causing you to consider switching in the first place, do not assume waiting is safer. Starting a switch in February or March gives the new firm plenty of time to take over before next year's deadlines.
What if my current accountant says I have to wait?
They do not get to decide. The client relationship is yours to end at any time — your accountant cannot require you to wait until a year-end, a deadline, or any other date. Professional clearance is a courtesy between firms, not permission for you to leave. A regulated accountant (ICAEW, ACCA, IFA, etc.) is bound by their professional body to cooperate with a handover within a reasonable timeframe.
Can I switch right before my VAT return is due?
Technically yes, but timing matters. HMRC agent authorisation codes can take a week or two to arrive by post, so a switch a few days before a VAT deadline risks the new firm not being authorised in time. The cleanest move is to let the imminent VAT return be filed by whichever firm is currently authorised, then begin the switch the day after — start of the next VAT quarter is the textbook clean break.
The full Switching Accountants series
The pillar plus five companion spokes — everything you need to switch with confidence.
Switching accountant — pillar guide
The full process, start to finish, with the reassurance that the new firm does the heavy lifting.
The step-by-step process
Engagement letter, AML check, clearance, records, HMRC authorisation — in order.
What is a professional clearance letter?
Why it isn't 'permission' to leave, and why it's almost never a problem.
Your records, data and software
What transfers, what stays in your cloud accounting account, and the 'lien' exception.
What if my old accountant won't cooperate?
Fee disputes, slow responses, and the escalation route to their professional body.
Signs it's time to switch
The six common patterns — and how a proactive accountant changes the picture.
Ready to switch? RR makes it effortless.
We send the professional clearance letter, collect your records, and get authorised with HMRC — so you barely lift a finger. Most clients tell us the only regret is not switching sooner.
We do almost all the work
Professional clearance letter to your old firm, records collected, HMRC agent authorisation done online. Your part: two emails and a quick ID check.
Switch any time of year
You do not have to wait for year-end. We pick the cleanest handover point so you do not pay twice for overlapping work.
Chartered, IFA-supervised
A regulated practice. Your old accountant is professionally bound to cooperate within a reasonable timeframe, and your records and HMRC position stay protected throughout.
IFA-supervised UK chartered practice · four UK offices · switch handled from clearance to HMRC authorisation
About the author
Mehmood Rajoka, Managing Partner, RR Accountants
Managing Partner at RR Accountants — a UK practice supervised by the Institute of Financial Accountants. RR handles dozens of accountant switches every year — clearance, records, HMRC authorisation, software handover — so clients barely lift a finger.
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This guide is general information about switching UK accountants. It is not personal tax advice. For advice tailored to your situation, speak to a regulated UK accountant. HMRC's agent authorisation mechanics and professional-body conduct rules can change — verified against primary sources as of . Re-check before acting.