IR35 contract checklist: 10 clauses to check before you sign

Use this checklist on any contract between your limited company and an agency or client. For each clause, ask two questions: what does it say, and does it match how the work will really happen?

1. Substitution

Good: your company can send a suitably qualified substitute, with refusal only on objective grounds, and pays them. Red flag: client consent at its "absolute discretion", or "the Consultant shall personally perform". More on substitution.

2. Services and scope

Good: a defined project, deliverables and acceptance criteria. Red flag: a vague job description, or the client may assign "such other duties as it reasonably requires".

3. Additional work and change control

Good: new work needs a written change request agreed on price. Red flag: open-ended additional services — see mutuality of obligation after PGMOL.

4. Manner of performance

Good: your company decides how, when and where the services are performed, subject only to genuine practical needs. Red flag: "in accordance with the reasonable instructions of the Client". More on control.

5. Hours and location

Good: flexible, linked to deliverables. Red flag: fixed core hours, timesheets approved by a line manager, mandatory on-site days without a practical reason.

6. Fees and financial risk

Good: fixed price or milestone payments; defects fixed at your own cost and in your own time. Red flag: paid for time regardless of outcome, overtime rates, paid when idle.

7. Insurance and liability

Good: your company carries professional indemnity and public liability insurance and is liable for its own errors. Neutral: it's expected of businesses, so it helps only a little.

8. Equipment and expenses

Good: you provide your own equipment and bear your own costs. Neutral: client system access and security passes are normal and carry little weight.

9. Integration and benefits

Good: you're described as an independent contractor with no staff benefits. Red flag: holiday pay, sick pay, staff perks, line management, managing the client's employees, appraisals.

10. Termination and exclusivity

Good: commercial termination terms (for example, for breach or on completion), freedom to work for other clients. Red flag: employee-style notice periods, restrictions on other work.

Then check the reality

Clauses are only half of it. Tribunals can disregard terms that don't reflect the true agreement, so write down how the engagement will actually work and compare it clause by clause. Where they differ, either change the contract or change the practice.

Do it in minutes

IR35 Checker runs this checklist on your actual contract, compares it with your answers about working practices, flags contradictions and suggests replacement wording. See the sample report.

General information, not legal or tax advice. If the stakes are high, have a specialist review your final contract.