Ask a managing partner what breaks first in January and they won't say the software or the deadline. They'll say people. The 2025/26 self-assessment returns are due by 31 January 2027, around twelve million taxpayers are in scope, and the returns themselves are rarely the problem. What breaks the practice is everything around them - clients who go quiet until the second week of January, records that arrive incomplete, and a phone that rings all day while the people who should be preparing returns answer it instead.
This is operational guidance for practice owners and managers, not tax or compliance advice. On the technical treatment of any return, your usual references and HMRC guidance govern.
January is a capacity problem, not a calendar problem
The deadline is fixed and known months ahead; that's not what hurts. What hurts is the shape of the work. The paper deadline passes quietly on 31 October, Christmas eats December, and clients resurface in mid-January expecting a two-day turnaround - so the usable runway collapses into the worst possible weeks. Front-loading is the obvious fix and clients won't cooperate: chase harder and you burn goodwill, wait and you compress everything into January. Last cycle, roughly 11.5 million returns were filed by 31 January with around a million still outstanding - and the fines (a £100 penalty, then £10 a day, plus interest) are the smaller cost. The bigger one is partners burning out and client trust eroding through a rushed month.
Underneath it all is a simple truth: the constraint is your senior people's hours. Every hour a fee-earner spends chasing a missing bank statement or answering "have you got my return yet?" is an hour not spent preparing or reviewing one.
MTD just added a second flood
Making Tax Digital for Income Tax began in April 2026 for the first cohort (income over £50,000), and it changes the arithmetic. Those clients now file quarterly updates plus a final declaration, while everyone else still files the usual annual return - a double workload during the busiest period, with up to several times the submission touchpoints per MTD client. Each quarterly cycle brings its own wave of "which figure goes where?", "did you get my receipts?" and "what do I owe?" - and there are three more cohorts coming in later years. The enquiry volume that used to spike once a year is becoming a steady drumbeat, and it lands on the same front desk.
Where the practice leaks time
Map busy season and the drain is rarely the returns themselves:
- Client chasing - records that don't arrive, and the endless follow-ups to get them.
- Status questions - "is my return done?", "what do I owe?", "have you filed it?" - answered one call at a time by people who should be preparing returns.
- The January call spike - everyone contacts you at once, and the phone wins over the workpapers.
- Records arriving unstructured - messy files that need untangling before anyone can review them.
- Onboarding new clients mid-crunch - high-intent enquiries that either convert or walk, at the worst possible moment.
None of this is skilled work. It's front-desk work being done by fee-earners because there's no one else to catch it.
Keep the front desk off the fee-earners' desks
The fix isn't heroics or a seasonal hire you have to train in January (which often costs more in partner time than it saves). It's separating the front-desk load from the technical work:
- Answer the enquiry flood at the front desk, not the fee-earner's desk. Status questions, deadline questions and general queries handled and logged, so preparers stay on returns.
- Automate the chase. Structured, repeated requests for records with reminders - so chasing doesn't consume senior time or goodwill.
- Set your own cut-offs and hold them. Internal deadlines per client, communicated early; late data pauses rather than triggers a scramble.
- Capture new-client enquiries instantly. Busy season is also prospecting season - don't let a good enquiry ring out because everyone's heads-down.
- File every query on the right record. So nothing is repeated and anyone can pick up where the last conversation left off.
This is where Odjo for Accounting fits: it answers client calls, WhatsApp and emails in more than 20 languages, chases outstanding records, books calls and files every query on the right client record - so the busy-season noise lands on the front desk instead of the people preparing returns. But the principle is process, not product. If you're doing this manually, do it religiously: front-desk work off the fee-earners, chasing automated, cut-offs held.
Frequently asked questions
Why is January so hard if the deadline never changes?
Because the work doesn't arrive evenly. Clients go quiet before Christmas and resurface in mid-January, so the real working window collapses into a few weeks. It's a capacity problem - the constraint is your senior people's hours - not a calendar one.
How does MTD for Income Tax change busy season?
The first cohort (income over £50,000) has filed quarterly since April 2026, plus a final declaration - so those clients now generate several times the touchpoints, overlapping with everyone else's annual returns. It turns a once-a-year spike into a recurring load, with more cohorts to come.
Should we just hire seasonal staff for January?
Sometimes, but onboarding a temporary preparer during peak - training them on your systems and workpapers when seniors have no spare hours - can cost more in partner time and rework than the crunch you're solving. Taking the front-desk load off fee-earners is usually the higher-leverage fix.
What's the single biggest time drain in busy season?
Client chasing and status questions - getting records in, and answering "is it done yet?" - handled by people who should be preparing returns. Automating the chase and answering queries at the front desk frees the hours that actually matter.
The takeaway
The self-assessment deadline doesn't punish firms that start late; it punishes firms that can't absorb the volume when it finally arrives - and MTD has added a second, quarterly flood on top. The returns aren't the bottleneck; the chasing, the status calls and the January spike are. Move that load off your fee-earners, automate the chase, hold your own cut-offs, and January becomes a busy month instead of a broken one.
