The April 6 CIS Change That Could Cost Builders 20% of Their Income for Five Years — and Most Haven't Heard of It

Published: March 2026 | Author: ComplianceAlert | Category: Construction Compliance, HMRC, CIS Publish path: /blog/cis-changes-april-2026 Target keywords: CIS changes April 2026, gross payment status 2026, CIS nil returns 2026, construction industry scheme changes, CIS supply chain fraud penalty Word count: ~1,400

---

Imagine you've spent years building a solid contracting business. Your CIS Gross Payment Status is secure — that means you receive full payment from clients without the 20% deduction at source. Your cash flow depends on it.

Now imagine HMRC contacts you. A subcontractor you paid 18 months ago has been investigated. They were involved in a fraudulent supply chain scheme. You had no idea.

Under the rules that apply until April 5, 2026: HMRC can suspend your GPS for up to one year. That's painful — 20% stripped from every payment you receive — but it's survivable. You get through it, you rebuild, you move on.

Under the rules that apply from April 6, 2026: it's five years.

Five years of 20% deductions on every single CIS payment you receive. Five years of cash flow destruction. Five years of penalty — for someone else's fraud.

This change is buried in Finance Act technical guidance. It received almost no coverage in the construction trade press. Nine days from now, it becomes law. Most construction firms have no idea it's coming.

---

What Gross Payment Status Is — and Why Losing It Destroys Cash Flow

Under the Construction Industry Scheme (CIS), subcontractors fall into two categories:

With GPS: You receive 100% of your payment. You manage your own tax liability at the end of the year.

Without GPS: Your contractor deducts 20% from every payment you receive and hands it to HMRC as a tax advance. That's 20% of your gross income — gone, immediately, on every invoice.

For most subcontractors and smaller contractors, that 20% deduction is the difference between a healthy cash flow and a business that's constantly scrambling. A sole trader bringing in £80,000 a year loses £16,000 annually to the 20% deduction. A firm turning over £500,000 loses £100,000.

HMRC can strip GPS if it finds evidence of fraud, compliance failures, or — and this is the new wrinkle — if it determines you were part of a fraudulent supply chain, whether you knew it or not.

Previously, the maximum suspension was one year. From April 6, it's five years.

---

Three CIS Changes Landing on April 6

The GPS extension is the most severe change, but it arrives alongside two others that compound the risk:

Change 1: GPS 5-Year Bar for Supply Chain Fraud

The Finance Act provisions taking effect April 6 extend HMRC's power to suspend Gross Payment Status from one year to five years where fraud is found — including supply chain fraud.

The critical word is "knew or should have known."

HMRC doesn't need to prove you were an active participant in the fraud. If investigators determine that you should have identified red flags — unverified subcontractors, unusual payment patterns, workers without confirmed CIS registration — that may be sufficient to trigger the five-year bar.

Real scenario: You're a roofing contractor with a steady roster of 12 subbies. One of them — someone you've been paying for two years — turns out to have been operating under a stolen CIS registration number. HMRC traces the fraud back through the supply chain. They determine you should have spotted the irregularity during verification. Your GPS is suspended.

Under the old rules: one year of 20% deductions. Under the new rules: five years.

At average subcontractor income levels, that's a six-figure cash flow hit over the suspension period.

Change 2: CIS NIL Returns Are Mandatory Again

Several years ago, HMRC removed the requirement to file a CIS return in months where you made no subcontractor payments. Many construction firms got used to simply not filing in quiet months.

From April 6, that exemption is gone. NIL returns are mandatory again.

If you paid zero subcontractors in April, you still need to log in to HMRC CIS Online by May 19 and file a NIL return. If you paid zero in May, same again by June 19.

What happens if you miss it: Automatic penalty. HMRC's penalty structure for late CIS returns starts at £100 and escalates. There is no grace period, no warning letter, and no room for discretion.

This catches firms that haven't logged in to the CIS system in months. If your last CIS return was January and you assumed you didn't need to file in February or March because you had no payments — you may already be in the penalty zone.

Change 3: Ongoing Subcontractor Monitoring (Not Just Initial Verification)

Previously, CIS compliance meant one thing: verify a subcontractor in HMRC CIS Online before you pay them for the first time. Check their name, UTR, and registration status. Done.

From April 6, the expectation shifts to ongoing monitoring.

If a subcontractor's compliance status changes after you first verified them — they miss returns, HMRC opens an investigation, their registration lapses — you may now carry liability for payments made while their status was compromised.

In practice: this means periodic checks on active subcontractors, not just a one-time verification box-tick.

---

The Supply Chain Trap Most Contractors Don't See Coming

The part of this that catches even experienced contractors off guard is the supply chain liability.

You don't need to be directly paying a fraudulent subcontractor. If you use a labour agency, a gang-master, or a larger subcontractor who in turn uses subbies with CIS issues — you may be in the exposure zone.

Construction supply chains are often layered: main contractor → subcontractor → sub-subcontractor → labour supply. HMRC's new enforcement posture means it is looking upward through that chain to see who benefited from fraudulent arrangements.

The firms most at risk:

• Scaffolders and roofers who rely on labour gangs where individual CIS verification isn't consistently checked
• Groundworks and civils firms where multiple layers of subcontracting are common
• Main contractors who assume sub-subcontractor compliance is the specialist's responsibility
• Any firm that has grown its subcontractor list rapidly and hasn't done a systematic verification review

---

What to Do Before April 6

You have nine days. Here's what matters most:

Step 1: Log in to HMRC CIS Online and pull your subcontractor list Review every active subcontractor. Check their verification status. Flag any with unresolved HMRC issues or whose registration status shows any irregularity.

Step 2: File any overdue NIL returns If you haven't filed a return for any month this year where you made no subcontractor payments, do it now. The penalty clock starts from the filing deadline, not from when HMRC contacts you.

Step 3: Document everything Create a written record of your verification checks: date, subcontractor name, UTR, status confirmed. This documentation is your evidence if HMRC investigates. Without it, "I checked" is not a defence.

Step 4: Set monthly NIL return reminders The CIS filing deadline is the 19th of each month. Set a recurring calendar reminder. Even zero-payment months need a return from April 6 onwards.

Step 5: Review your supply chain structure If you regularly use labour agencies or sub-subcontractors, document who they use. Consider asking for written confirmation of their subcontractors' CIS verification. This may feel excessive — but it's the kind of record HMRC will look for if they investigate.

Step 6: Take stock of workers with unusual payment arrangements Ghost worker schemes — arrangements where payments go to fictitious subcontractors or where identities are misused — are HMRC's primary enforcement target. If anything in your payment records looks irregular, resolve it before April 6.

---

April 6 Isn't Just a CIS Date

While CIS dominates, April 6 brings a wider compliance wave for construction firms:

April 1 (4 days): National Living Wage rises to £12.71/hour. All directly employed workers aged 21+ must be at the new rate from April 1 or HMRC enforcement kicks in automatically.

April 6: Statutory Sick Pay becomes a day-one right. All employees are eligible from their first day of work — no three-day waiting period. Employment contracts that specify waiting periods need updating.

April 6: If you're a sole trader with income above £50,000, Making Tax Digital for ITSA applies. You need compatible MTD software and quarterly digital filing from this date.

April 7: The Fair Work Agency is formally established and takes over enforcement of NMW, holiday pay, and SSP compliance from HMRC. Construction labour supply chains — particularly agency workers and labour supply companies — are an identified enforcement priority.

---

The Practical Reality

For most small construction firms, the April 6 CIS changes create three distinct risks:

1. The NIL returns trap: Firms that haven't logged in to CIS in months, assuming silence was fine. From April 6, silence means automatic penalties.

2. The supply chain trap: Firms who have never done a systematic verification of their subcontractor list and don't realise they could be exposed for someone else's fraud.

3. The GPS cash flow trap: Firms whose GPS is at risk — perhaps they've had compliance issues before — and who don't realise HMRC now has five years to hold it rather than one.

None of these are things HMRC will write to warn you about in advance. They operate through penalties and enforcement actions.

---

How ComplianceAlert Helps

CIS guidance changes through GOV.UK updates, HMRC press releases, and Finance Act technical notes. Most construction firms have no reliable way to track these changes until they've already missed a deadline.

ComplianceAlert monitors HMRC CIS, HSE, NLW, CDM regulations, asbestos requirements, and 8 other UK regulators — and sends UK construction firms plain-English alerts when something changes in their sector.

When the NIL return requirement went back in. When the GPS rules changed. When the Fair Work Agency started targeting construction labour supply chains. You get an alert — not a fine.

£19/month. 14-day free trial. No credit card required.

👉 compliancealert.co.uk/construction

---

Sources

• HMRC: Construction Industry Scheme — guidance for contractors and subcontractors
• Finance (No. 2) Act 2023 — CIS enforcement provisions
• Employment Rights Act 2025 — day-one rights provisions
• HMRC: National Minimum Wage rates April 2026
• Making Tax Digital for Income Tax — HMRC guidance
• Fair Work Agency — GOV.UK establishment announcement

---

ComplianceAlert provides regulatory monitoring for UK small businesses. This article is informational — not legal or tax advice. For advice specific to your situation, consult a qualified solicitor or accountant.