Does IR35 Apply To The Self-Employed In The UK?

If you regularly work with freelancers or contractors, you’ve probably heard a lot about IR35 and the “off‑payroll working rules.” The big question many small businesses ask is simple: does IR35 apply to the self‑employed you hire?

Short answer: IR35 generally targets arrangements where an individual provides services through an intermediary (often a limited company, sometimes called a “personal service company” or PSC). If you directly engage a genuine sole trader, IR35 usually doesn’t apply - but employment status still matters for tax and employment law. Getting that status call wrong can be costly.

In this guide, we’ll break down how IR35 works from a client/business perspective, when it applies (and when it doesn’t), how to assess status, and the practical steps to manage risk when engaging contractors.

What Is IR35 (Off‑Payroll Working) And Why Do Businesses Care?

IR35 is HMRC’s framework designed to tackle “disguised employment.” It applies where an individual supplies their services to a client via an intermediary (commonly their own limited company) and, but for that intermediary, they would be an employee for tax purposes.

Key points for businesses:

• IR35 is about tax status, not contractual labels. HMRC looks at what actually happens in practice.
• Since April 2021, medium and large private sector clients - and all public sector clients - are responsible for deciding IR35 status and, if “inside,” for operating PAYE/NICs (via the “fee‑payer”).
• Small private sector clients are exempt from making the IR35 assessment; in those cases, the contractor’s intermediary remains responsible.

The drivers here are risk and cost. If a role is inside IR35 and you (or the fee‑payer in your supply chain) don’t treat it correctly, HMRC can pursue the unpaid tax and NICs, plus interest and penalties. That’s why it’s critical to understand whether you’re within scope - and to document your decisions with care.

Does IR35 Apply To The Self‑Employed?

It depends on what “self‑employed” means in your situation. Broadly:

• If you directly contract with a bona fide sole trader (no intermediary company), IR35 itself doesn’t apply. However, HMRC can still challenge the engagement as “employment” for tax if the working relationship looks like employment in reality. You still need to assess status.
• If you engage an individual through their limited company (a PSC) or certain partnerships, the off‑payroll rules can apply. In this case, you must determine status (unless you qualify as a small company).

This distinction often trips people up. “Self‑employed” is sometimes used loosely to mean “not on payroll,” but IR35 is specifically targeted at intermediary arrangements. For direct engagements with individuals, your focus isn’t IR35 as such - it’s whether you’re treating a worker as a contractor when they should be taxed (and possibly treated) as an employee.

If you’re weighing up the differences between engagement types, it helps to revisit the employment status tests and the classic indicators of control, substitution and mutuality of obligation (among others). These tests underpin both IR35 decisions and direct contractor vs employee assessments.

When Do The Off‑Payroll Working Rules Apply - And Who Is Responsible?

From a client perspective, the off‑payroll rules apply if all of the following are true:

• Services are provided by an individual through an intermediary (typically their limited company); and
• The individual would be an employee for tax if you contracted with them directly (the hypothetical “but for the intermediary” test); and
• You are a medium or large private sector client (or any public sector client).

There’s a small company exemption in the private sector. You are “small” if you meet two of these thresholds (Companies Act):

• Turnover of £10.2m or less
• Balance sheet total of £5.1m or less
• 50 employees or fewer

For certain unincorporated clients, there’s a similar turnover test (£10.2m). If you’re small, the contractor’s intermediary is responsible for determining IR35 status and accounting for the tax - not you. If you’re medium or large, you must:

• Make a status determination using reasonable care.
• Issue a Status Determination Statement (SDS) to the worker and the party you contract with.
• Operate PAYE/NICs (or ensure the “fee‑payer” does) if the role is inside IR35.
• Have a process to handle disputes about your status decision.
• Keep records. HMRC expects good documentation.

In multi‑party chains, the “fee‑payer” (the party paying the PSC) usually carries the duty to deduct PAYE/NICs. But HMRC’s transfer of debt rules can move the liability up the chain if someone fails to pass on the SDS or comply. Solid supply‑chain due diligence is key.

How Do You Assess Employment Status In Practice?

Whether you’re engaging a sole trader or a PSC, you need to consider the same core tests. No single factor is decisive, but HMRC and tribunals commonly look at:

Control

How, when and where is the work done? The more control you exercise over hours, methods, location, supervision and approvals, the more it looks like employment.

Personal Service vs Substitution

Is the individual required to perform the services personally, or can they provide a suitably qualified substitute? A genuine, unfettered right of substitution (that’s actually workable in practice) points toward self‑employment.

Mutuality Of Obligation (MOO)

Are you obliged to provide ongoing work, and is the individual obliged to accept it? Open‑ended on‑going obligations are more consistent with employment, while project‑based, deliverable‑focused engagements support self‑employment.

Financial Risk & Integration

Does the individual bear financial risk, provide their own equipment, hold insurance, invoice per project, and work with multiple clients? Being integrated into your organisation (using employee benefits, attending staff appraisals, etc.) looks like employment.

HMRC’s CEST tool can be part of your process, but it’s not a silver bullet. It relies on accurate inputs and doesn’t always capture MOO. Use it alongside a documented, fact‑based assessment and sensible contract terms that reflect reality. If you’re unsure, a written assessment paired with a tailored Contractors Agreement can help you evidence your reasoning.

Best Practice If You Engage Sole Traders Or PSCs

Clear paperwork and consistent working practices go a long way. Here are practical steps to reduce risk when you engage independent talent.

1) Decide The Right Engagement Model

• Employee: Ongoing role, high control, integrated into your team? Put them on payroll and use a proper Employment Contract.
• Contractor (PSC or sole trader): Project‑based, deliverables‑driven services with independence and genuine substitution rights? Use a tailored Contractors Agreement or, where relevant, a Sub‑Contractor Agreement.

Don’t take a “contractor for convenience” approach if the reality is employment. HMRC focuses on substance over form.

2) Align Reality With The Contract

Your contract should mirror how things actually work. Consider:

• Genuine substitution: Build an unfettered right to provide a qualified substitute (including practical mechanisms and your right to refuse on reasonable grounds like security or competence).
• Limited control: Specify deliverables, milestones and quality standards, not daily timesheets and micro‑management.
• No mutuality: Frame engagements around discrete projects or statements of work, with no obligation to offer or accept further work.
• Business indicators: Require contractors to maintain insurance, use their own equipment, invoice for services and correct defective work at their cost where appropriate.
• No employee benefits: Avoid holiday pay, sick pay, pensions, or staff perks that suggest employment.

If you’re unsure how these factors apply to your role, revisit the distinctions in worker vs employee status and ensure your processes line up with the status you intend.

3) Document Your Status Determination (Where IR35 Applies)

If you’re medium/large (or public sector) and engaging via a PSC:

• Undertake a status assessment using reasonable care and document the facts you relied on.
• Issue the SDS to the worker and supplier, and retain records.
• Set up PAYE/NICs via the fee‑payer if inside IR35.
• Keep the determination under review if working practices drift.

4) Manage Your Supply Chain

Where agencies are involved, build obligations into your contracts so you receive and pass on the SDS correctly, and ensure the fee‑payer understands its tax obligations. Keep an audit trail. HMRC can transfer liabilities if the chain breaks down.

5) Consider Sector‑Specific Rules

Some industries have extra schemes. For example, if you’re in construction, the Construction Industry Scheme (CIS) can apply separately to IR35, affecting tax deductions and verification. Ensure your finance team understands the interaction.

6) International Contractors

If the worker or client sits overseas, off‑payroll rules can apply differently (for example, where the client is “wholly overseas” with no UK connection). Cross‑border engagements also raise permanent establishment, withholding and data protection questions. If you engage talent abroad, it’s wise to get advice and review your approach to engaging overseas contractors before you commit.

Common Scenarios And How To Handle Them

We’re A Small Company - Do We Need To Worry About IR35?

If you’re “small” under the Companies Act thresholds, the off‑payroll rules generally don’t require you to make the IR35 status call. The contractor’s company remains responsible. That said, HMRC can still challenge arrangements, and you should still assess whether your engagement looks like employment. Good contracts, clear practices and a file note of your reasoning are still smart risk management.

We Want To Extend A Contractor For Another Year

Longer engagements increase the risk of “drift” toward employment characteristics (greater control, integration, rolling obligations). If your contractor has been on a day‑rate in your office 9‑5 for 18 months, consider whether the role is really a job. Either reset working practices around deliverables and independence, or convert the role to employment with an Employment Contract and put them on payroll.

The Contract Has A Substitution Clause, But We’d Never Allow It

HMRC looks at reality. A theoretical right of substitution that can’t be used (because security passes, onboarding, or your approvals effectively block it) won’t help. If you include a right of substitution, make it genuine and workable - and make sure your managers understand and respect it in practice.

We Use A Statement Of Work With Milestones - Is That Safer?

Project‑based statements of work help show there’s no mutuality of obligation and can support contractor status - provided the day‑to‑day reality matches. Pair your SoW with a robust Contractors Agreement, and keep work orders, invoices and communications aligned to deliverables, not attendance.

We’re Switching From Sole Traders To PSCs To Avoid Risk

Switching an individual from sole trader to PSC doesn’t automatically change their status. HMRC will still ask: “But for the company, would this be employment?” If nothing else changes, IR35 risk may increase (because off‑payroll rules could now apply). Focus on working practices first - the label comes second.

Contracts And Documents That Help Evidence Your Status

Contracts don’t decide status on their own, but they’re vital evidence of the intended relationship. For independent engagements, consider:

• Contractors Agreement for services provided by a PSC or sole trader, paired with project‑specific statements of work.
• Sub‑Contractor Agreement if you’re a supplier appointing specialist help under a head contract (with a clear flow‑down of obligations and independence).
• Insurance clauses (e.g. professional indemnity, public liability) and obligations to provide equipment and rectify defects.
• Non‑exclusive engagement terms and the right to work for multiple clients.
• Audit and compliance clauses to manage IR35 processes in your supply chain (including SDS distribution and fee‑payer obligations where applicable).

And when the role is really a job, protect your business properly with a tailored Employment Contract that sets out duties, confidentiality, IP ownership, notice, probation and post‑termination restrictions.

If you’re still deciding which route fits, revisit the practical differences in contractor vs subcontractor roles and, above all, make sure the reality of the engagement (control, substitution, mutuality, financial risk) matches the paperwork.

Compliance Tips To Stay On The Right Side Of HMRC

• Use reasonable care for every status decision. Keep a short written assessment on file explaining the factors you considered and why.
• If the off‑payroll rules apply, issue an SDS, share it down the chain, and confirm who the fee‑payer is. Review if scope or working practices change.
• Train hiring managers not to “creep” toward employment behaviours (fixed hours, mandatory meetings, approvals for time off) in independent roles.
• Use statements of work, deliverable‑based milestones and outcome‑oriented acceptance criteria rather than time and attendance.
• Require contractors to maintain appropriate insurance and to invoice for completed deliverables (not weekly timesheets, where possible).
• Watch sector‑specific rules (e.g. CIS in construction), and align finance processes accordingly.
• For cross‑border engagements, assess tax nexus and local compliance early - cross‑check your approach to overseas contractors to avoid surprises.

If you’re unsure about a borderline case, it’s sensible to get tailored advice before onboarding. A small adjustment to scope, deliverables or process at the outset can make your status position far clearer.

Key Takeaways

• IR35 targets intermediary arrangements (typically PSCs). If you directly engage a genuine sole trader, IR35 doesn’t apply - but you still must assess employment status for tax and manage the engagement accordingly.
• Medium/large private sector and public sector clients must make status determinations, issue SDSs and ensure PAYE/NICs are operated for “inside IR35” roles. Small private sector clients are generally exempt from making the determination.
• Status turns on substance: control, substitution, mutuality of obligation, financial risk and integration. Contracts help, but working practices matter more.
• When the role is really a job, hire as an employee and use an Employment Contract. For genuine independent roles, use a robust Contractors Agreement or Sub‑Contractor Agreement that aligns with reality.
• Document your reasoning, keep your supply chain compliant (SDS and fee‑payer obligations), and train managers to avoid “employee‑like” behaviours in contractor engagements.
• Borderline or international scenarios warrant specific advice. A short review up front can prevent costly HMRC disputes later.

If you’d like help assessing IR35 risk, setting up the right documents, or deciding whether a role should be employee or contractor, you can reach us at 08081347754 or team@sprintlaw.co.uk for a free, no‑obligations chat.