There is no standard timescale for changing accountants, and any firm promising you a fixed one is guessing. What can be said honestly is this: the process is a sequence of short stages, each measured in days rather than months when everyone cooperates, and the total depends on three variables: the outgoing firm’s responsiveness, the complexity of your affairs, and how quickly you personally sign and send things. Understanding the stages tells you far more than any promised number would.
The stages, and what each one waits on
A switch moves through five gates, each with its own bottleneck:
- Your decision and the new engagement letter. Waits on: you. This stage takes exactly as long as your deliberation plus a signature.
- Identity checks at the new firm. Waits on: you providing documents. Regulated firms must verify new clients before acting; with documents supplied promptly this is one of the quickest stages.
- Professional clearance. Waits on: the outgoing firm. The new accountant’s letter goes out fast; the reply is the least predictable element of the whole process.
- Records transfer. Waits on: the outgoing firm again, and on how your records are held. Cloud-held books can change hands almost immediately; paper archives and old desktop files take longer.
- Agent authorisation with HMRC. Waits on: processing and your approval steps. Authorisations for each tax (Self Assessment, VAT, PAYE, Corporation Tax) are set up per service, so an employer with several registrations has more to switch than a sole trader with one.
Notice what is absent: no stage waits on negotiation, confrontation or complexity of law. The switch is administrative from end to end.
What genuinely stretches the timeline
Four things account for nearly every slow handover:
- An unresponsive outgoing firm. Professional bodies expect timely cooperation with clearance, but expectation is not a stopwatch. Polite chasing from the new firm, and occasionally a nudge from you as the client, is the remedy.
- Unpaid fees. Outstanding bills are the most common reason records move slowly. Settling legitimate fees promptly, and keeping any genuine dispute separate from the handover, removes the leverage problem.
- Work in progress. If your old firm is mid-way through accounts or a return, someone must finish it, and agreeing who adds a negotiation the standard process does not have.
- Your own turnaround. Signatures, identity documents and authorisation approvals that sit in an inbox for a fortnight add a fortnight. The client is a bigger variable than most clients think.
Complexity multiplies steps, not difficulty
A sole trader with a single Self Assessment registration has one authorisation to move and one set of records. A limited company with payroll and VAT has several authorisations, more records, and possibly a payroll cycle that must not miss a beat mid-transfer. Employers should plan the payroll handover around a specific pay period so submissions under current GOV.UK guidance continue without interruption. None of this makes switching harder; it makes it longer, in proportion to how many registrations you hold.
Planning around your deadlines
Rather than asking “how long does it take?”, the more useful planning question is “what is my next filing, and will the switch complete before it?” Raise that question with the new firm on day one. A competent one will map your obligations and either complete the handover in time or agree explicitly who files the next thing due. Switching just after a major filing gives the process maximum clear road, which is why timing features in how to switch accountants. If you are still weighing whether to move at all, when should a small business change accountants? comes first, and what happens after you accept a quote details the onboarding stages on the new firm’s side.
Frequently asked questions
Can a switch happen quickly if a deadline is close?
Often, yes: firms are used to taking on clients near deadlines and can prioritise authorisation and the urgent filing. Tell the new firm about the deadline in the first conversation, not after signing.
Who chases the old accountant if clearance is slow?
The new firm leads the chasing as a matter of professional routine. A short message from you to your old accountant asking them to respond usually moves things faster than another firm-to-firm letter.
Does my business stop being compliant during the handover?
No. Your registrations and obligations continue uninterrupted; only the agent acting for you changes. The risk to manage is a filing falling due mid-switch with nobody clearly assigned to it, which is solved by assigning it.
Can I speed things up myself?
Materially. Provide identity documents immediately, approve authorisation requests the day they arrive, settle outstanding fees with the old firm, and grant the new firm access to your cloud records yourself rather than waiting for a transfer.
Is there a worst time of year to switch?
Peak filing season means both firms are busiest, so responses slow. It is never a wrong time to leave a failing arrangement. Just build in more patience, or agree that the old firm completes the imminent filing first.
Start the clock with us
We tell every prospective client at the quote stage which of their deadlines we can safely take on and how we will sequence the handover. See what our small business accountancy service includes, or request a quote. The first stage of the timeline is one form.