IR35 and Off-Payroll Working: Your Complete Guide to Stay Compliant in 2024

IR35 and Off-Payroll Working: Your Complete Guide to Stay Compliant in 2024

IR35—formally the "Intermediaries Legislation"—is one of the most misunderstood rules in UK tax. If you work through a limited company and contract to a public-sector body, or if you're inside a private-sector client's payroll, you need to understand it. Get it wrong, and you face back-tax bills, penalties, and stress. Get it right, and you maximise legitimate tax efficiency while staying completely within the law.

This guide explains what IR35 is, who it affects, how to assess your status, and what to do next.

What Is IR35?

IR35 is a UK tax rule designed to prevent tax avoidance by people who would otherwise be employees, but who work through an intermediary (usually a limited company) to reduce their tax and National Insurance contributions.

In plain terms: if you do work that would make you an employee if you worked directly for the client, then IR35 catches you—even though you're technically self-employed through your limited company.

When IR35 applies, your limited company must deduct income tax and National Insurance from your drawings, much as if you were on a payroll. The goal is to put you in roughly the same tax position as a direct employee would be.

Read the official HMRC guidance on IR35.

Who Does IR35 Affect?

IR35 applies to you if you meet all of these conditions:

• You work through an intermediary (almost always a limited company)
• You provide personal services (you do the work yourself; you can't easily delegate)
• Your client treats you as if you were an employee in practice (control, integration, mutuality of obligation)
• You fall into one of the off-payroll working regimes (public sector or private sector, depending on the current rules)

The Public Sector Off-Payroll Rule (Since 2017)

If your client is a public-sector body (NHS, local authority, civil service, public-sector quango), IR35 always applies unless you're genuinely in business on your own account. There is no escape—the onus is on your client to operate PAYE.

The Private Sector Off-Payroll Rule (Since April 2021)

From April 2021, the off-payroll working rules were extended to large private-sector clients (broadly, those with a turnover exceeding £10.9 million or more than 50 employees). The responsibility for assessing whether IR35 applies shifted from the contractor to the client or the agency.

Small and micro businesses (those below these thresholds) are not subject to the private-sector rule, so IR35 assessment remains your responsibility.

Check HMRC's full off-payroll working guidance.

How to Determine Your Employment Status

The key question: would you be an employee if you worked directly for the client?

HMRC and the courts consider several factors:

Control

• Does the client dictate how, when, and where you work?
• Can they impose disciplinary measures?
• Do they require you to follow their procedures and policies?

If yes to most: likely employment-like. IR35 may apply.

Substitution

• Can you send a substitute to do your work if you're unavailable?
• Would the client accept that substitute, or insist on you personally?

A genuine right to substitute (exercised in practice) is a strong indicator of self-employment. A right that's illusory or never used suggests employment.

Mutuality of Obligation

• Must you accept all work the client offers?
• Must the client always have work for you?

If mutual obligations exist: employment-like. If work is ad-hoc and either party can walk away: self-employed.

Integration

• Are you integrated into the client's business (team, inductions, company events)?
• Or do you work separately, perhaps alongside other contractors?

Integration suggests employment. Separation suggests self-employment.

Risk and Investment

• Do you invest in tools, training, or premises?
• Can you make a loss on the contract?
• Are you responsible for correcting defective work at your own expense?

Yes to these: stronger self-employment indicators.

Real-world example: A software contractor working 40 hours per week at a bank's office, required to attend team meetings, use the bank's systems, follow the bank's processes, and subject to the bank's performance reviews—would almost certainly be caught by IR35, regardless of the limited company structure. The contractor lacks genuine substitution rights, integration is tight, and control is client-led.

The Responsibility Shift: Who Decides?

Who assesses whether IR35 applies has changed:

Public Sector

Your public-sector client (or the agency, if they engage you through an agency) is responsible for determining your status and operating PAYE if IR35 applies. You should request their determination in writing.

Private Sector (Large Clients)

Your private-sector client or agency (if they meet the size threshold) must make the determination. They must tell you their decision and provide reasoning. If they say you're out of IR35, that's their formal decision, and you can rely on it (with some limits).

Private Sector (Small Clients) & Self-Employed Assessment

If your client is small (below the threshold) or you're genuinely in business (e.g., you have multiple clients, set your own rates, invest significantly), the responsibility to assess IR35 falls on you. You should document your position thoroughly and keep evidence.

See HMRC's guidance on who is responsible for the determination.

What Happens If IR35 Applies?

When IR35 catches you:

1. Your limited company must operate PAYE on payments to you (or you, personally, if self-employed)

2. Tax and National Insurance are deducted before you receive draws or salary

3. You file a Self-Assessment return as if you were employed, even though you own the company

4. Allowable deductions are limited to genuine business expenses (not the wide deductions available to truly self-employed people)

5. Unpaid tax, interest, and penalties apply if you've been non-compliant

However, if you remain genuinely self-employed (out of IR35), you retain more flexibility in deductions and no obligation to operate PAYE.

Practical Steps to Comply

1. Get a Formal Determination

If you work for a large private-sector client or a public-sector body, request a written determination of your IR35 status. Keep it. If the client says you're out of IR35, you have legal protection (a so-called "status determination statement").

2. Document Your Position

Keep records showing:

• Your contract terms
• Evidence of control (or lack of it)
• Any substitute work you've performed
• Multiple client relationships (if relevant)
• Investment in your business
• Genuine business decisions and risks

This protects you if HMRC queries your assessment later.

3. Operate PAYE Correctly

If IR35 applies (or if you're uncertain), the safest approach is to operate PAYE through your limited company. This removes the immediate risk of underpayment and demonstrates compliance. Your accountant should advise on payroll software and deadlines.

4. File Accurately

Complete your Self-Assessment return honestly, declaring all income and claiming only genuine business expenses. If your accountant flags an IR35 risk, address it proactively.

5. Review Regularly

Your status can change. If your working pattern shifts (e.g., more control imposed, or integration increases), reassess. Conversely, if you move to a smaller client or diversify your client base, your position may improve.

Common Pitfalls

• Ignoring a client's determination. If a large private-sector client says you're in IR35, you should comply—continuing to work as if you're out can trigger an audit and back-tax demands.
• Assuming a contract clause defines your status. Contracts alone don't determine employment status; it's the reality of the working relationship that matters.
• Operating without professional guidance. IR35 is complex and fact-specific. A mistake can be costly. Many contractors benefit from a formal review by a tax professional.
• Failing to keep records. If you can't evidence your position, HMRC will assume the worst.

IR35 and Your Accounts

If IR35 applies, your limited company's accounts should:

• Show salary and PAYE deductions from you
• Reflect genuine business expenses only
• Explain the basis of your income recognition (services rendered to client X, for instance)

Your accountant will guide you on the correct accounting treatment. This keeps your records audit-ready and demonstrates transparency.

Recent Changes and Upcoming Risks

IR35 has been under scrutiny for several years. The government has signalled possible reforms, but any changes take time to legislate. In the meantime:

• HMRC is actively enforcing the off-payroll rules in both sectors
• Employment tribunal cases continue to clarify the boundary between employment and self-employment
• Contractors in newly regulated sectors (e.g., healthcare locums, agency workers) should monitor for scope creep

Stay informed by checking the official HMRC guidance regularly and discussing changes with your tax adviser.

Working with a Tax Professional

Given the complexity and cost of getting IR35 wrong, most contractors benefit from professional support. A licensed tax adviser can:

• Review your contracts and working arrangements
• Give a formal opinion on your IR35 status
• Liaise with your client or agency for a status determination
• Set up compliant PAYE if needed
• Defend your position if HMRC raises an enquiry
• Help you claim the right expenses within the rules

This is not a DIY area for most people. The risk of a six-figure tax bill—plus interest and penalties—far outweighs the cost of professional advice.

Summary

IR35 is a real constraint on contractor tax planning, but it's not a trap if you understand it:

• Understand the rules: Control, substitution, integration, and mutuality matter more than contract labels.
• Get a formal determination if your client is large or public-sector.
• Document your position and keep records.
• Operate PAYE if IR35 applies, or if you're uncertain.
• Review regularly and seek professional advice when circumstances change.
• Work with a tax professional to ensure compliance and minimize risk.

For a tailored review of your own situation, book a consultation with one of our licensed tax professionals. We serve UK contractors, expats, and small-business owners across the USA, UK, and UAE, and we can help you navigate IR35 with confidence.

To explore our contractor tax services and pricing, visit our pricing page.

Frequently asked questions

Does IR35 apply if I work through my limited company but have only one client?

Not automatically. Having one client doesn't trigger IR35 by itself. What matters is the nature of your working relationship: do you have genuine control over how you work, can you truly substitute someone else, and are you genuinely running a business? Many one-client contractors are still legitimately self-employed. However, if your one client also controls how, when, and where you work, and you have no real substitution rights, IR35 is likely to apply. Have a professional review your contract and working practices.

What's the difference between a status determination statement and my own assessment?

A status determination statement (SDS) is a formal written determination made by your client or agency (if they're large or public-sector). It carries legal weight: if they say you're out of IR35 and you rely on it, you have statutory protection. Your own assessment is your opinion. If HMRC disagrees with your assessment and you can't prove your position, you're liable for back tax. Always request an SDS if your client is obligated to provide one.

Can I appeal an IR35 determination from my client?

There's no formal appeal to the client, but you can challenge their determination by seeking your own professional advice, negotiating further with the client, or ultimately by disputing an HMRC assessment through the tax tribunal if you're later challenged. In practice, most contractors who disagree with a client's determination should seek tax professional guidance to understand their options and risks.

What penalties apply if I'm caught working 'in IR35' without operating PAYE?

Penalties can include back income tax, unpaid National Insurance contributions (employee and employer), interest at the statutory rate (currently 8% per annum), and tax geared penalties of up to 100% of the unpaid tax in cases of deliberate evasion. On a six-figure income over several years, this can amount to tens of thousands of pounds. Early disclosure and correction minimizes penalties.

If I have multiple clients, am I automatically out of IR35?

Multiple clients is a strong indicator of self-employment, but it's not a guarantee. HMRC and the courts look at the overall picture. If your main client still controls your work, and your other clients are minimal, IR35 might still apply to your primary engagement. Conversely, if you genuinely divide your time, set your rates, and manage your own business across several clients, you're more likely to be out of IR35 across the board. The key is substance, not just structure.