CIS vs Employment: Key Differences for Subcontractors

Understanding CIS vs employment status is one of the most important — and most misunderstood — distinctions in the construction industry. Being registered under CIS does not make you self-employed. CIS is a tax collection mechanism, not a determination of your employment status. If HMRC decides you're actually an employee, the tax consequences can be significant for both you and your contractor.

This guide explains the key differences between CIS self-employment and employment, how HMRC tests your status, what the consequences of getting it wrong are, and what changed from April 2026 with HMRC's new anti-fraud rules.

CIS Subcontractor vs Employee: The Key Differences

Whether you're a CIS subcontractor (self-employed) or an employee depends on the reality of your working arrangement — not just what your contract says or which box your contractor ticks. HMRC looks at the substance of the relationship.

Factor	CIS subcontractor (self-employed)	Employee
Control	You decide how, when, and where you do the work	The contractor tells you how, when, and where to work
Substitution	You can send someone else in your place	You're personally required to do the work
Financial risk	You risk your own money (buying materials, fixing mistakes at your cost)	The contractor bears the financial risk
Equipment	You provide your own tools and equipment	The contractor provides tools and equipment
Multiple clients	You work for several contractors	You work for one contractor exclusively
Integration	You're engaged for a specific project or task	You're part of the contractor's permanent team
Payment	You invoice for completed work (task or project-based)	You receive regular wages (weekly/monthly)
Benefits	No holiday pay, sick pay, or pension from the contractor	Entitled to holiday pay, sick pay, pension auto-enrolment

No single factor is conclusive. HMRC looks at the overall picture.

How HMRC Tests Employment Status

The HMRC employment status test uses three main factors to determine whether someone is genuinely self-employed or actually an employee:

1. Control

The most important factor. If the contractor controls how you do the work (not just what work is done), this points towards employment.

Self-employed indicators:

• You decide your own methods and approach
• You choose which tools and materials to use
• You set your own working hours
• You're judged on results, not supervised during the process

Employment indicators:

• The contractor tells you how to do the job step by step
• You work set hours determined by the contractor
• A supervisor checks your work methods (not just the finished product)
• You attend contractor-organised training or meetings

2. Personal Service and Substitution

Can you send a substitute to do the work in your place? If yes, this strongly suggests self-employment.

Self-employed indicators:

• You have the right to send a qualified replacement
• You pay the substitute yourself
• The contractor accepts the substitute without unreasonable restrictions

Employment indicators:

• You're personally required to do the work
• The contractor would not accept someone else in your place
• Any substitution right is theoretical only (never actually used)

3. Mutuality of Obligation

Mutuality of obligation (MOO) considers whether obligations exist between you and the contractor. Following the Supreme Court's 2024 PGMOL ruling, MOO is generally considered to exist within any individual engagement where one party agrees to do work and the other agrees to pay for it (the "wage-work bargain"). The more relevant question now is whether there are ongoing obligations beyond a specific engagement.

Self-employed indicators:

• There's no ongoing commitment between engagements
• Each job is a separate contract
• You can turn down future work without consequence

Employment indicators:

• The contractor expects you to be available on an ongoing basis
• You can't refuse work without risking the relationship
• There's an assumption of continuous, open-ended engagement beyond the current task

Employment Status Examples in Construction

Example 1 — Likely self-employed: James is an electrician who works for three different contractors. He provides his own tools, quotes for each job individually, and can send a qualified colleague if he's unavailable. He invoices each contractor separately and takes financial risk if materials are wasted. James is likely a genuine CIS subcontractor.

Example 2 — Likely employed: Sarah works exclusively for one building firm. She turns up at 7am every day to the same site, uses the firm's tools, is told which tasks to do by a site manager, and is paid a fixed day rate regardless of output. She has no right to send someone else in her place. Despite being registered for CIS, Sarah may actually be an employee.

Example 3 — The grey area: Tom is a plasterer who works mainly for one contractor but occasionally takes other jobs. He provides his own hand tools but the contractor supplies scaffolding and heavy equipment. He's paid per room plastered (not per hour) and can refuse jobs. Tom's status is borderline — the outcome depends on the full picture of his working arrangement.

Consequences of Wrong Employment Status Under CIS

Getting employment status wrong has consequences for both the worker and the contractor:

For the Contractor

If HMRC determines that a CIS subcontractor should have been treated as an employee:

• Unpaid PAYE and NI: The contractor owes the Income Tax and employer/employee National Insurance that should have been deducted — potentially going back several years
• Penalties: Up to 100% of the unpaid tax for deliberate misclassification
• Loss of gross payment status: Contractors who misclassify workers can lose their GPS
• Employment rights claims: The worker may claim holiday pay, sick pay, and pension contributions

For the Worker

• Lost employment rights: If you're actually an employee but treated as CIS, you miss out on holiday pay, sick pay, pension auto-enrolment, and redundancy protection
• Tax complications: Your Self Assessment return may be incorrect if you claimed expenses only available to the self-employed
• NI gaps: You may have paid the wrong class of National Insurance

April 2026 Changes: Stricter HMRC Enforcement

From 6 April 2026, HMRC has significantly strengthened its tools for tackling CIS fraud, including false self-employment in construction:

"Knew or Should Have Known" Test

Under new sections 62A and 62B, HMRC can take action against businesses anywhere in the supply chain that "knew or should have known" that payments or returns were connected with fraudulent tax evasion. This means:

• Main contractors can be liable for lost tax even if the fraud happened further down the chain
• End clients may face tax liability if they should have spotted warning signs — including obvious false self-employment arrangements

GPS Revocation

Contractors found to be involved in CIS fraud can have their gross payment status cancelled by HMRC — with a 5-year ban on reapplying (up from the previous 12-month period).

Penalties Up to 30%

HMRC can charge penalties of up to 30% of the lost tax to the business, its directors, or connected persons where CIS fraud is identified.

These changes make it more important than ever for both contractors and subcontractors to ensure their working arrangements genuinely reflect self-employment.

How to Check Your Status

HMRC's CEST Tool

HMRC provides the Check Employment Status for Tax (CEST) tool. Answer questions about your working arrangement and get HMRC's view on whether you're employed or self-employed.

Important: CEST results are not legally binding, but HMRC has said it will stand by the result if you provided accurate information. It's a useful starting point.

What to Do If You're Unsure

1. Review your working arrangements honestly against the tests above
2. Use the CEST tool to get HMRC's indicative view
3. Check your contract — does it reflect reality? A contract calling you "self-employed" doesn't override the facts of how you actually work
4. Keep evidence of your self-employment: records of multiple clients, own tools, substitution arrangements, financial risk taken
5. Consider professional advice if your situation is complex or you're close to the borderline

Frequently Asked Questions

Does CIS registration make me self-employed?

No. CIS registration is a tax collection mechanism — it tells contractors which deduction rate to apply to your payments. It does not determine your employment status. You could be registered for CIS but still be an employee in HMRC's view if the reality of your working arrangement points to employment.

Can I be CIS and employed at the same time?

You can have both CIS self-employment and separate PAYE employment — for example, working as a self-employed subcontractor on weekends while employed full-time elsewhere. However, you cannot be an employee of a particular contractor and simultaneously be that contractor's CIS subcontractor. It's one or the other for each working relationship.

What if my contractor insists I register as CIS when I think I'm an employee?

This is a red flag. If the reality of your work looks like employment (set hours, contractor's tools, no substitution right, paid wages), you may have employment rights regardless of how the contractor classifies you. You can contact ACAS (0300 123 1100) for advice on employment rights, or HMRC for tax status questions.

How far back can HMRC investigate employment status?

HMRC can generally go back 4 years for standard assessments, 6 years for careless misclassification, and up to 20 years for deliberate misclassification. From April 2026, the "knew or should have known" test also means businesses elsewhere in the supply chain can be held liable.

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This guide is for informational purposes only and does not constitute tax, legal, or financial advice. Tax rules change frequently. Always verify current requirements on GOV.UK or consult a qualified accountant for your specific situation.

Official Sources

• Check employment status for tax - GOV.UK
• Employment status: self-employed and contractor - GOV.UK
• Construction Industry Scheme (CIS) - GOV.UK
• CIS: what you must do as a subcontractor - GOV.UK