IR35 Legal Contractor Agreement Template UK
Operating through a Personal Service Company exposes UK contractors to significant tax risk if their working arrangements resemble employment under Chapter 10 of the Income Tax (Earnings and Pensions) Act 2003, commonly known as IR35. Without a properly drafted contractor agreement, HMRC can challenge your outside-IR35 status, potentially leaving you liable for unpaid income tax and National Insurance Contributions dating back years. A robust IR35 contract must clearly demonstrate substitution rights, control limitations, and the absence of mutuality of obligation — the three pillars HMRC and tribunals scrutinise most closely. It should also align precisely with your actual working practices to withstand a Status Determination Statement review. Protect your business and tax position with a legally sound, IR35-compliant contract built specifically for UK contractors operating via a PSC — generate yours now.
Generate your IR35 Agreement free →Key clauses in a IR35 Agreement
Right of Substitution
This clause grants the contractor the genuine right to send a suitably qualified substitute to perform the services in their place, without requiring the client's approval of a specific individual. Under IR35 case law, including Autoclenz Ltd v Belcher [2011], a credible and unrestricted substitution right is one of the strongest indicators of self-employment outside IR35.
Mutuality of Obligation
This clause explicitly states that the client is under no obligation to offer work and the contractor is under no obligation to accept it, preventing an ongoing expectation of continuous engagement. HMRC's CEST tool and IR35 tribunals consistently treat mutuality of obligation as a key determinant of employment status under Chapter 10 ITEPA 2003.
Control and Direction
This clause defines that the contractor retains full control over how, when, and where the services are delivered, with the client specifying only the outcome required. Limiting the client's right to direct the contractor's working methods is critical evidence of genuine business-to-business contracting under IR35 legislation and HMRC's Employment Status guidance.
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Does having an IR35-compliant contract automatically mean I am outside IR35?
No — a well-drafted contract is necessary but not sufficient on its own. HMRC and tribunals will look beyond the written terms to assess the actual working practices under the 'reality of the arrangement' principle established in cases such as Autoclenz Ltd v Belcher [2011]. Your day-to-day conduct on the engagement must consistently reflect the outside-IR35 terms written into your contract.
Who is responsible for issuing a Status Determination Statement under the off-payroll working rules?
Since the Off-Payroll Working reforms of April 2021, medium and large private sector clients are legally required to issue a Status Determination Statement (SDS) to the contractor and the fee-payer under Chapter 10 ITEPA 2003. The SDS must state whether the engagement is inside or outside IR35 and provide reasoned grounds for that determination. Small companies, as defined under the Companies Act 2006, are currently exempt and responsibility remains with the contractor's PSC.
Can I use the same IR35 contract template for every client engagement?
Using a generic template as a starting point is acceptable, but each contract should be tailored to reflect the specific services, deliverables, and working arrangements of the individual engagement. HMRC may challenge contracts that appear identical across multiple clients, as this can suggest the terms do not genuinely reflect the working reality. Reviewing and updating your contract each time you take on a new engagement is strongly recommended to accurately represent the nature of that specific relationship.
The information on this page is for general informational purposes only and does not constitute legal advice. Contracto generates AI-assisted contract templates — they are not a substitute for advice from a qualified solicitor. For high-value or complex engagements, always seek independent legal review.