TL;DR
- Switching accountants takes 2–4 weeks and your new accountant handles the entire process for you
- Professional clearance is a standard ethical requirement, not something to worry about. Your old accountant must cooperate.
- You do not need to contact HMRC directly. Your new accountant submits the 64-8 agent authorisation form on your behalf.
- Year-end is the cleanest transition point, but mid-year switches are perfectly normal. Don’t let timing keep you stuck.
💡Quick reference summary. Continue reading for comprehensive analysis and context.
You have decided it is time to change accountants. Perhaps you have already read our guide on when to switch and recognised the warning signs. Now comes the practical question: what actually happens when you make the move?
The good news is that switching accountants in the UK is a well-established, regulated process. It is not complicated, it is not disruptive, and your new accountant does almost all of the work. The entire transition typically completes within two to four weeks.
This guide walks through every step: notifying your old firm, what professional clearance means and why it exists, how records are transferred, how HMRC agent authorisation works, what to prepare before you start, and every common concern addressed honestly.
The 5-Step Process for Switching Accountants
Every accountant switch in the UK follows essentially the same path. Here is the process from start to finish, with realistic timelines for each stage.
Notify your old accountant
Day 1Let your current accountant know you intend to move. Check your engagement letter for any notice period. Most firms require 30 days’ notice or notice at the end of a billing period. Be professional and factual. You do not owe them an explanation, though most people briefly mention they are looking for a different type of service.
New accountant sends professional clearance
Days 2–14Your new accountant writes to your old firm. This is a formal letter required by ACCA and ICAEW ethical codes, asking if there is any professional reason they should not accept the appointment. Your old accountant is obligated to respond. This is standard practice for every accountant switch in the UK.
Records handover
Days 7–18Your old accountant transfers all working papers, filed accounts, tax computations, payroll records, and documentation to your new firm. If you use cloud accounting software like Xero or QuickBooks, your new accountant will be added as an adviser and the old firm’s access will be removed.
HMRC agent authorisation (64-8 form)
Days 7–21Your new accountant submits a 64-8 form to HMRC to register as your tax agent. This can be done digitally through HMRC’s online agent services in a few days, or by post in two to three weeks. HMRC will send you a notification to confirm. You simply approve it.
Onboarding with your new accountant
Week 2–4Your new accountant reviews your financial position, sets up their internal systems, and begins providing ongoing services. They will walk you through any changes to processes or reporting. Within two to four weeks, you are fully transitioned with no gap in service.
Typical Timeline
Professional clearance usually takes 7 to 14 days. HMRC digital agent authorisation can complete in a few days. The entire transition, from first conversation to fully operational, typically takes two to four weeks. Steps 2, 3, and 4 often run in parallel, not sequentially.
Professional Clearance Explained
Professional clearance is the part of the process that sounds most intimidating but is actually the most straightforward. Understanding what it is and why it exists will remove any anxiety about the switch.
What professional clearance is
When you appoint a new accountant, they are ethically required to write to your previous accountant. This is a formal letter asking one specific question: is there any professional reason why we should not accept this appointment?
This requirement exists under the ethical codes of both ACCA and ICAEW (the two main UK accounting bodies). Its purpose is to protect you. It ensures your new accountant is aware of any outstanding issues, such as unpaid fees, ongoing HMRC investigations, or incomplete work that might affect the handover.
What happens in practice
In the vast majority of cases, the old accountant simply replies confirming there are no issues. The letter goes out, a response comes back, and the process moves forward. It is a formality.
If there are legitimate issues to disclose (for example, an ongoing HMRC enquiry into your tax affairs), the old accountant will mention them. This is not a reason to panic. It simply means your new accountant is fully informed and can plan accordingly.
Key Facts About Professional Clearance
What Your New Accountant Handles for You
One of the biggest misconceptions about switching accountants is that you will be stuck in the middle, chasing both firms and dealing with HMRC paperwork. That is not how it works.
Your new accountant manages the transition process. Here is what they take care of:
Your Only Job
Provide your new accountant with your basic details (UTR, company number, software login) and approve the HMRC agent authorisation when notified. That is the extent of your involvement. Everything else is handled for you.
HMRC Agent Authorisation: The 64-8 Form
The 64-8 form is how HMRC knows that your new accountant is authorised to act on your behalf. It covers Corporation Tax, Self Assessment, PAYE, and VAT, depending on which services you need.
How it works
Your new accountant completes and submits the 64-8 form. HMRC then sends you a notification (either digitally or by post) asking you to confirm the authorisation. Once you approve it, the new agent is registered and the old agent's authorisation is automatically removed.
Digital Route
Via HMRC online agent services
Postal Route
Paper 64-8 form sent to HMRC
Most modern accountants use the digital route, which is faster and more reliable. Either way, the process is handled entirely by your new accountant. You do not fill in the 64-8 form yourself.
Mid-Year vs Year-End: When Is the Best Time to Switch?
The short answer: year-end is cleaner, but mid-year is absolutely fine. Do not let timing keep you with the wrong accountant.
Why year-end is the cleanest transition point
Switching after your year-end accounts have been filed means a complete, signed-off set of records is handed over. Your new accountant starts with a clean opening position. There is no need to unpick work-in-progress or reconcile part-year records.
Why mid-year switches work perfectly well
Your old accountant hands over records up to the point they stopped working. Your new accountant picks up from there. If you use cloud accounting software like Xero or QuickBooks, the data is continuous regardless of who is managing it. There is no gap and no duplication.
Good Times to Switch
- •After year-end accounts are filed
- •After your corporation tax return is submitted
- •At the start of a new VAT quarter
- •Any time you are unhappy with your current service
Avoid If Possible
- •The week before a filing deadline
- •January (self-assessment season)
- •The day before your VAT return is due
- •During an active HMRC enquiry (switch after it concludes)
The Bottom Line on Timing
If your current accountant is causing real problems, the best time to switch is now. The cost of waiting for a “perfect” moment almost always exceeds the minor inconvenience of a mid-year transition. Your new accountant has done this before and knows how to manage it.
What to Prepare Before Switching
Your new accountant will tell you exactly what they need, but having these items ready will speed up the process. Most of this information is readily available in your existing records or online accounts.
Switching Accountants Checklist
UTR number (Unique Taxpayer Reference)
Found on HMRC correspondence or your online tax account
Company registration number
Available on Companies House or your certificate of incorporation
VAT registration number
If VAT registered. Found on your VAT certificate or HMRC online account
Last filed annual accounts
Available on Companies House or from your current accountant
Last Corporation Tax return (CT600)
Your current accountant should have a copy, or check your HMRC online account
Last Self Assessment return
If you file personally as a director. Available through your HMRC personal tax account
Accounting software login details
Xero, QuickBooks, FreeAgent, or whichever platform you use
Payroll details
If you run payroll. Number of employees, PAYE reference number, current payroll provider
Don't Worry If You Don't Have Everything
Your new accountant can obtain most of this information through the handover process or directly from HMRC and Companies House. Having it ready speeds things up, but not having it will not stop the switch from happening.
Common Fears About Switching Accountants (Debunked)
Every business owner has the same set of concerns when they think about switching accountants. Here is the reality behind each one.
“My old accountant will be difficult”
Reality: Professional bodies require accountants to cooperate with the clearance process. Your old accountant cannot refuse to respond to the professional clearance letter, cannot refuse to hand over your records, and cannot withhold information to make the transition harder.
Most accountants handle departures professionally. They understand that clients move for many reasons and that obstructing the process would damage their own professional standing. If you are worried about an awkward conversation, remember that your new accountant handles most of the contact.
“I'll lose my data”
Reality: Your accounting records belong to you. Your old accountant has a legal and professional obligation to hand over your books, records, and any documents you provided to them. Working papers they created (such as tax computations and accounts preparation notes) should also be provided.
If you use cloud accounting software, the data lives in the cloud, not on your accountant's systems. Switching accountants means changing who has adviser access to your account. The data itself stays exactly where it is.
“HMRC will be confused”
Reality: HMRC has a well-established process for changing tax agents. The 64-8 form is specifically designed for this purpose. HMRC processes thousands of agent changes every week. When your new accountant registers as your agent, the old authorisation is automatically removed. There is no overlap, no confusion, and no risk of correspondence going to the wrong place.
“It will be expensive to switch”
Reality: Most new accountants absorb the transition costs as part of their standard onboarding. You should not be charged extra by your new firm for the switching process itself. Your old accountant may invoice you for any outstanding work up to the handover date, but they cannot charge you for the act of handing over your records.
If your old accountant tries to charge a “disengagement fee” or a fee for releasing your records, check your engagement letter. Unless such a fee was explicitly agreed in writing, they are unlikely to be entitled to it. Your new accountant can advise you on this.
Red Flags During the Handover (and What to Do)
The transition process is smooth in the vast majority of cases. However, some old accountants do not handle departures well. Here are the warning signs and the steps your new accountant will take.
Old accountant does not respond to the clearance letter
What happens: Your new accountant will send a follow-up letter. If there is still no response after a reasonable period (typically 14 to 21 days), they can proceed with the appointment. Non-response is treated as clearance granted by the professional bodies. If the silence continues, your new accountant can report the matter to ACCA or ICAEW.
Old accountant charges for handing over your records
What happens: Your records belong to you. Unless your engagement letter explicitly includes a records-release fee, they are not entitled to charge for this. Your new accountant will write to them citing the relevant professional standards. If necessary, a complaint can be made to their professional body. Some firms withhold records until outstanding fees are paid, but this applies to their own work product (like tax computations), not your source documents and data.
Handover delays beyond 30 days
What happens: Prolonged delays are a breach of professional conduct. Your new accountant will escalate through formal channels. Meanwhile, they can obtain much of what they need directly from HMRC, Companies House, and your cloud accounting software. A delayed handover is frustrating but rarely prevents work from beginning.
The Irony of Difficult Handovers
If your old accountant is being obstructive during the handover, it validates your decision to leave. A professional firm handles departures professionally. Difficult behaviour during the transition tells you everything you need to know about the service culture you were paying for.
Check Your Engagement Letter First
Before you notify your old accountant, review your current engagement letter. This is the contract between you and your accounting firm. Pay attention to these clauses:
Notice period
Most firms require 30 days’ notice or notice by the end of a billing cycle. Some have no notice period at all. Honour whatever is stated in your letter.
Outstanding fees
You may owe fees for work already completed but not yet billed. This is normal and should be settled. However, you should not be charged for work that has not been done.
Records retention
Your engagement letter may state that records will be held until fees are paid. This usually applies to the accountant’s own working papers, not your original source documents.
Termination clause
Some letters include specific termination procedures. Follow them to ensure a clean break. If in doubt, your new accountant can review the letter and advise.
Switching With Cloud Accounting Software
If you use Xero, QuickBooks, or similar cloud accounting software, the transition is even simpler. Your data does not need to be “transferred” in the traditional sense because it lives in the cloud.
How the software handover works
Your new accountant is added as an adviser on your account. Your old accountant's adviser access is removed. The books, transaction history, reports, and attachments all stay exactly where they are. There is no export, no import, and no risk of data loss.
If you currently give your old accountant the login credentials to your own account (rather than them having a separate adviser login), change your password after the transition. Your new accountant should always use their own adviser access, not your personal login.
Desktop Software Users
If you use desktop accounting software (like Sage 50), your old accountant will need to provide a backup file of your accounting data. Your new accountant may also recommend migrating to a cloud platform during the transition, which is often easier to do at the point of switching rather than as a separate project later.
What Good Onboarding Looks Like
The quality of your new accountant's onboarding process tells you a lot about how they will handle your affairs going forward. Here is what you should expect from a well-run transition:
A clear onboarding checklist
Your new accountant should give you a simple list of what they need and by when. No ambiguity, no back-and-forth.
A named point of contact
You should know exactly who is handling your transition and how to reach them.
An initial review of your financial position
Within the first few weeks, your new accountant should review your current books, identify any issues, and flag opportunities.
Proactive communication
Your new accountant should keep you updated on the progress of the clearance, records transfer, and HMRC authorisation.
No surprises on fees
The scope of work and fees should be clearly agreed before the transition begins. There should be no additional charges for the onboarding process itself.
Frequently Asked Questions
How long does it take to switch accountants in the UK?
Can I switch accountants mid-year?
What is professional clearance and why is it needed?
Will my old accountant be difficult about leaving?
Do I need to tell HMRC when I change accountant?
What happens to my records when I change accountant?
What if my old accountant charges me for releasing my records?
Is it expensive to switch accountants?
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