IR35, formally the off-payroll working rules, is tax legislation that determines whether a contractor working through a personal service company should be taxed as an employee for that engagement.
Who decides status
For engagements with medium and large private-sector clients, and all public-sector clients, the end client is responsible for assessing employment status and deducting tax and National Insurance where the rules apply. Small private-sector clients remain exempt, leaving the assessment with the contractor's own company.
Tax rules depend on individual circumstances and can change. This glossary is general information rather than personalised tax advice.