Triage for the Backlog: A Practical Guide to Historical Bookkeeping

Why Backlogs Accumulate (and Why They Matter Now)

Backlogs rarely happen all at once. They accumulate through a familiar sequence. A business grows faster than its bookkeeping capacity. A bookkeeper leaves. A sole trader prioritizes client work over their own administration. The monthly routine slips to quarterly, then annual, then "when I absolutely must file."

For years, this was merely untidy. But from 6 April 2026, Making Tax Digital for Income Tax Self Assessment becomes mandatory for businesses earning over £50,000 in total gross income from self-employment or property. This replaces annual tax returns with digital recordkeeping and quarterly submissions. A backlog is no longer a tidiness problem. It becomes a compliance risk.

Estimating the Real Effort

Before we triage, we should be clear-eyed about the scale of the work. A typical month of bookkeeping for a small business—100 to 200 transactions—takes an experienced bookkeeper 2 to 4 hours manually. That includes coding transactions, reconciling bank accounts, and handling VAT.

A two-year backlog, then, represents 48 to 96 hours of work. That is 6 to 12 working days. For a sole practitioner juggling client work, this is often untenable. For a practice with capacity, it is still a significant resource allocation. Industry observers note that bookkeeping and payroll together make up nearly 30% of the service mix in UK accountancy firms, and backlogs can consume disproportionate amounts of that time.

This is where we separate realistic planning from wishful thinking. You cannot clear a two-year backlog in a weekend. But you can compress the timeline significantly through triage and tooling.

The Triage Framework: What to Tackle First

Not all months in a backlog carry equal weight. Recent periods are more likely to have supporting documents, accessible bank feeds, and fresh memory of what transactions represent. The further back you go, the colder the trail. A pragmatic approach therefore works backwards from the present.

The "Good Enough" Threshold

Perfection is the enemy of done, particularly with historical data. A pragmatic approach focuses on materiality. Resolve significant discrepancies—anything that materially affects the accounts or tax position. For the rest, know when to stop.

Sometimes 95% accuracy across a three-year backlog is better than 100% accuracy on six months. The goal is not forensic precision on stale data. The goal is to get current, stay current, and manage risk appropriately.

Tool-Assisted Clearing: Compressing the Timeline

Manual ticking and tying is where the 2 to 4 hours per month comes from. Modern automated coding tools can compress this to 30 to 60 minutes per month by handling the routine transactions—direct debits, standing orders, recurring suppliers—leaving the bookkeeper to focus on genuinely ambiguous items.

This is not marketing hyperbole. The compression comes from eliminating the repetitive pattern-matching that humans do slowly and computers do quickly. A tool that has learned your chart of accounts, VAT codes, and supplier patterns can classify 70 to 85% of transactions automatically with high confidence. The remaining 15 to 30% still require human judgment, but that is a manageable review task rather than a wholesale coding exercise.

Research from accounting practice management suggests that firms increasingly use offshore capacity or automation to clear backlogs, freeing senior staff for client-facing work and strategic advice. This is a pragmatic resource allocation, not an abdication of responsibility.

When to Draw the Line and Start Fresh

There are circumstances where reconstruction is genuinely not worth it. If records are incomplete, if bank feeds are no longer available, if the client cannot provide supporting documents, the cost of perfect historical accuracy may exceed its value.

For limited companies with statutory filing obligations, you need clean accounts. But even here, you can establish verified opening balances from the last filed accounts and reconcile forward from a known-good position rather than attempting to reconstruct every transaction from inception.

For sole traders, the tax return is the binding document. If the backlog is severe, sometimes the most pragmatic approach is to prepare the tax return from the best available data, make appropriate adjustments, and then start fresh with current bookkeeping going forward. This is a conversation to have with the client's accountant, but it is often the right answer.

Staying Current: The Real Victory

Clearing the backlog is one thing. Staying current is what prevents it from accumulating again. This requires process, not heroics. Block regular time—weekly or fortnightly—for bookkeeping. Treat it as non-negotiable, like filing VAT returns or paying payroll.

The effort to stay current is far less than the effort to catch up. A month of transactions coded in real time takes 2 to 4 hours. The same month coded six months later takes longer because context is lost, bank feeds may have expired, and supporting documents are harder to locate.

Automation helps here too. A system that codes routine transactions as they appear turns monthly bookkeeping into a review task rather than a data entry marathon. Combined with bank feeds pulling transactions automatically, this reduces the effort to stay current to a manageable routine.