IR35 Explained: What NRI Contractors in the UK Need to Know

IR35 determines whether HMRC treats contractors as employees for tax purposes. For NRI professionals considering contract work in the UK — whether through a personal service company, umbrella company, or as sole traders — IR35 status has significant financial and visa implications. This guide covers the two regimes, key status tests, umbrella companies, and Skilled Worker visa restrictions.

IR35 Explained: What NRI Contractors in the UK Need to Know

IR35 is one of the most consequential and misunderstood pieces of UK tax legislation for contractors and self-employed professionals. For NRI professionals considering contract work in the UK — whether through a personal service company (PSC), an umbrella company, or as a sole trader — IR35 status determines whether HMRC treats you as an employee for tax purposes or as a genuinely independent contractor. Getting this wrong carries significant financial risk.

What IR35 Is

IR35 (formally the Intermediaries Legislation, first introduced in 2000 and significantly reformed in 2017 and 2021) is an anti-avoidance measure targeting disguised employment — situations where an individual provides services to a client through a limited company or other intermediary, but the working arrangement is substantively that of employment rather than genuine self-employment.

If HMRC determines that, but for the intermediary (your limited company), you would be considered an employee of the client, then IR35 applies. The effect: your income from that engagement is treated as employment income — subject to PAYE income tax and National Insurance — even though it is paid through your company.

The Two Regimes: Public Sector and Private Sector

IR35 rules differ by sector:

Public sector (since April 2017): The end client (the public sector organisation) is responsible for determining IR35 status and applying PAYE deductions if the engagement is inside IR35. This applies to government departments, NHS trusts, universities, and other public bodies.

Private sector (since April 2021): For medium and large private sector clients, the client is responsible for making the IR35 determination (issuing a Status Determination Statement — SDS). For small private sector clients (meeting the Companies Act definition of a small company), the responsibility remains with the contractor's own company.

Small company exemption: A private sector client is small if it meets at least two of three criteria:

  • Turnover is 10.2 million GBP or less
  • Balance sheet is 5.1 million GBP or less
  • Fewer than 50 employees

If your client is a small private sector company, you (or your PSC) are responsible for assessing your own IR35 status.

Determining IR35 Status: The Key Tests

HMRC and employment tribunals apply multiple tests derived from case law. The key factors:

1. Substitution: Can you send a genuine substitute to perform the work in your place? If the client has agreed in the contract that you personally must provide the services, this points toward employment. Genuine, unrestricted right of substitution (not limited by the client's approval) points toward outside IR35.

2. Control: Does the client control how, when, and where you work? Employee-like control (fixed hours, direct supervision, client equipment) points toward inside IR35. Contractor autonomy over method, location, and timing points toward outside.

3. Mutuality of Obligation (MOO): Is the client obligated to offer you work, and are you obligated to accept it? An ongoing engagement with automatic renewal, guaranteed hours, and no right to decline work resembles employment. Project-based engagements with defined deliverables and no expectation of continuation after project end point toward outside IR35.

4. Other factors: Financial risk (can you profit or lose from the engagement?), integration into the client's organisation (do you appear as an employee on their systems, attend staff meetings as a staff member?), and equipment provision all contribute to the assessment.

[CAUTION_FLAG: HMRC's Check Employment Status for Tax (CEST) tool (gov.uk/guidance/check-employment-status-for-tax) provides indicative status assessments but is not definitive. HMRC has stated it will stand behind CEST outcomes only if inputs are accurate and complete. Engage a specialist IR35 reviewer or employment tax adviser for any significant engagement.]

Consequences of Being Inside IR35

If an engagement is inside IR35:

  • The fee-payer (your client, or an agency between you and the client) must deduct PAYE income tax and National Insurance Contributions (NICs) from payments to your company before paying you.
  • Your company receives the payment net of tax — similar to receiving a salary.
  • You lose the tax efficiency of drawing dividends from your company on that engagement's income.
  • Your company cannot claim certain business expenses against that engagement's income.

Umbrella Companies as an Alternative

Many NRI contractors in the UK use umbrella companies as an alternative to operating a personal service company. With an umbrella company:

  • You become an employee of the umbrella company.
  • The umbrella company invoices the client/agency, receives payment, and pays you a salary after deducting PAYE income tax, employee NICs, the umbrella's margin, and employer NICs.
  • IR35 is effectively irrelevant — you are already employed by the umbrella.

Umbrella companies are regulated and the majority are legitimate, but HMRC has issued warnings about mini umbrella schemes and disguised remuneration arrangements that promise significantly higher take-home than a legitimate umbrella — these carry significant tax risk.

[CAUTION_FLAG: Only use umbrella companies registered on the FCSA (Freelancer and Contractor Services Association) or Professional Passport accredited lists. Do not use any scheme promising to retain more than approximately 85% of your day rate as take-home after all taxes and deductions — this is a red flag for non-compliant arrangements.]

Visa Considerations for NRI Contractors

Self-employment restrictions: The Skilled Worker visa does not permit self-employment. If you are on a Skilled Worker visa, you must be employed by your sponsor. Working through a personal service company where you are a director of that company and providing services to end clients would generally constitute self-employment for immigration purposes — this is not permitted on the Skilled Worker route.

[CAUTION_FLAG: The Skilled Worker visa prohibits self-employment and directorship of companies that are not your sponsor. If you wish to operate as a contractor through a PSC, you need an appropriate visa route (e.g., Innovator Founder, Global Talent, or indefinite leave to remain). Take immigration advice before establishing any contracting structure while on a Skilled Worker visa.]

Graduate and other routes: The Graduate visa, Youth Mobility Scheme visa, and Indefinite Leave to Remain all permit self-employment. If you are on one of these routes and want to contract via a PSC, IR35 rules apply fully and you are responsible for your own status determinations for small-client engagements.

Practical Steps for Contractors

  1. Understand which visa you hold and whether self-employment is permitted before establishing any contracting structure.
  2. Before signing a contract, have the working arrangements assessed by an IR35 specialist — not just the contract wording, but the actual working practices.
  3. Ensure your contract includes a genuine substitution clause and that your day-to-day working relationship with the client reflects contractor independence, not employment integration.
  4. Keep all CEST assessments, SDS documents, and working practice records as evidence of your IR35 determination.
  5. If using an umbrella company, verify it is FCSA or Professional Passport accredited.

This article is general information and does not constitute tax or immigration advice. IR35 legislation and HMRC guidance change. Consult a specialist IR35 adviser and a registered immigration adviser for advice specific to your situation.