The UK construction contractor sector comprises over 98,000 businesses generating close to £197 billion in revenue. It is also one of the most heavily regulated industries when it comes to tax — and in 2026, that regulatory burden increased again. If you are a contractor or subcontractor operating under the Construction Industry Scheme, working with specialist accountants for trades and construction contractors is not just a comfort: it is a practical necessity.

We work with a number of trades and construction businesses at Edward Harris, and the pattern we see repeatedly is straightforward. Contractors who rely on a generalist accountant tend to find out about compliance problems after they have already become expensive. Those who work with someone who knows CIS, the VAT reverse charge, and gross payment status inside out tend to stay ahead of HMRC rather than reacting to letters from them.

This post outlines why that distinction matters, what has changed recently, and what you should actually expect from an accountant who understands your industry.

The Construction Industry Scheme was updated materially from 6 April 2026. The most significant operational change for contractors is the introduction of mandatory nil returns. Previously, if you had no payments to subcontractors in a given month, there was some ambiguity around whether a return was required. That ambiguity is gone. You are now required to submit a CIS300 return to HMRC every month, even when the figure is nil.

Alongside that, the criteria for obtaining and retaining gross payment status have been tightened. Since April 2024, VAT compliance has been included in the tests — meaning a VAT return filed late or inaccurately can jeopardise a subcontractor’s gross payment status. The April 2026 reforms have built on this, adding new fraud penalties under the legislation introduced through AB25.

HMRC updated the CIS 340 guidance on 6 April 2026 to reflect these changes, and revised its internal compliance manual in late March. The pace of change here is worth noting: if your accountant is not actively monitoring these updates, there is a reasonable chance they are working from out-of-date assumptions.

None of this is designed to catch honest contractors out, but the consequences of falling behind are real — and they accumulate quickly if issues go unnoticed.

A generalist accountant can handle your year-end accounts, file your self assessment, and keep you compliant with the basics. That is genuinely useful. The gap appears when construction-specific issues arise — and they arise more frequently than most contractors expect.

Generalist practices tend not to flag things like the VAT domestic reverse charge proactively. They may not be on top of changes to gross payment status rules, or alert you when HMRC updates CIS compliance guidance. They are less likely to understand the cash flow dynamics of retentions, or the tax implications of different contract structures. When something does go wrong — a subcontractor’s gross payment status is withdrawn, say, or an incorrect deduction goes unspotted — the contractor is liable for the tax not deducted. That is a significant exposure, and one that a proactive specialist tends to catch before it becomes a problem.

HMRC has also been issuing what it calls ‘one to many’ letters to CIS contractors where its data suggests deductions may be incorrect. Contractors receiving these letters have 45 days to verify and correct their records. After that window closes, HMRC can open a formal compliance check, and the penalties if errors are confirmed are considerably higher. Knowing how to respond to one of those letters — and having your records in order — is the kind of thing a specialist handles routinely and a generalist often finds stressful.

For subcontractors, gross payment status is financially significant. Without it, the contractor paying you must deduct either 20% or 30% from your payments and pass that to HMRC. That is money out of your cash flow until you can reclaim it through your tax return — which can mean waiting months for funds you have already earned.

Gross payment status is granted when you meet HMRC’s compliance tests, which now include your VAT filing history as well as your direct tax record. It sounds straightforward, but the tests catch people out. A single late VAT return, a missed self assessment deadline, or an administrative oversight on a CIS return can all create problems.

Equally, if HMRC withdraws gross payment status from one of your subcontractors and you continue paying them gross because nobody flagged the change, the liability for the undeducted tax falls on you as the contractor. That is a real risk, and it is one that good CIS record-keeping — verifying subcontractor status before each payment period and maintaining that evidence — is specifically designed to prevent.

A construction-specialist accountant keeps this front of mind because they have seen what happens when it slips. In our experience, the businesses that run into CIS problems are rarely the ones being careless — they are often just the ones whose accountant did not flag the issue in time.

One practical advantage of working with a specialist practice in 2026 is that modern cloud accounting tools — Xero, QuickBooks Online, FreeAgent — can be configured specifically for construction workflows. CIS deductions can be tracked automatically, subcontractor verification records stored digitally, and monthly CIS300 returns prepared with far less manual effort than a spreadsheet-based approach allows.

This matters for Making Tax Digital as well. MTD for Income Tax Self Assessment is being rolled out progressively, and construction businesses — particularly sole trader contractors and landlords who also do subcontract work — need to be thinking about quarterly digital reporting now, not when the deadline is already upon them.

We use cloud accounting software with all our construction clients and configure it to reflect how they actually operate: retentions, CIS deductions, subcontractor payments, and VAT reverse charge all handled in one place. The difference in time spent on admin, and in the quality of the financial picture you get back, is substantial. An accountant still running paper systems or basic spreadsheets for a construction client is, frankly, creating unnecessary work for everyone.

When you are evaluating whether an accountant genuinely specialises in trades and construction, a few questions cut through the noise.

• Do they understand CIS end-to-end? Not just ‘we do CIS returns’ — but verification procedures, nil return requirements, gross payment status risks, and what happens when subcontractor status changes mid-contract.
• Do they know the VAT domestic reverse charge? This applies to most VAT-registered construction businesses and affects how invoices are raised and how VAT is accounted for. Misapplying it is a common and costly error.
• Are they using cloud accounting? In 2026, an accountant recommending paper records for a CIS contractor is setting you up for compliance headaches down the line.
• Are they ACCA or ICAEW qualified? Regulated accountants carry professional indemnity insurance, are subject to continuing professional development requirements, and have a regulatory body you can escalate to if something goes wrong.
• Are they proactive? The value of a specialist is not just knowing the rules — it is telling you about changes before they affect your business, not after.

If the answer to most of those is uncertain, it is worth having a conversation elsewhere. The cost of switching is lower than most people assume, and the risk of staying with the wrong accountant in a tightly regulated industry like construction is higher than it looks.