IR35 Status Dispute Letter Template & Generator

If you need to dispute an IR35 inside determination with your client, a written letter is the recommended first step — it creates a clear record and shows you're pursuing the matter formally. Below is what a strong ir35 status dispute letter should include, plus a free tool to generate yours.

What this letter needs to cover

• Formally dispute the status determination
• Set out why the contract should be outside IR35 based on substitution
• Control and mutuality of obligation tests
• Request a review of the determination
• Reference the Check Employment Status for Tax CEST tool if applicable

Why an inside IR35 determination might be wrong

IR35 status should reflect the genuine reality of how you work — the level of control the client has, whether you can send a substitute, and your level of financial risk. If your client has determined you're "inside IR35" without properly assessing these factors, or has applied a blanket policy without individual assessment, this can be legitimately challenged.

What to include before you send it

• A request for the specific reasoning behind the determination, if not already provided
• Your own assessment of key status factors — control, substitution rights, and financial risk
• Reference to your right to formally disagree under the client-led status disagreement process
• A request for the determination to be reviewed

Your right to a formal status disagreement process

Since the off-payroll working rules came into effect, clients are required to have a process allowing you to formally disagree with a status determination, and to respond with reasons within 45 days. If a client has no such process, or ignores your challenge, this is itself a compliance failure on their part.

Frequently Asked Questions

What happens if the client refuses to change the determination?
You can seek independent advice on your status, and in some circumstances this may need to be resolved through HMRC guidance or, in disputed cases, through tribunal.

Does an inside IR35 determination affect how I'm paid?
Yes — it generally means the fee-payer must deduct tax and National Insurance as if you were an employee for that engagement, which is exactly why getting the determination right matters financially.

See our full letter template & generator library for related letters, or use our free checkers for guidance specific to your situation.