Substitution is a very important component when determining your IR35 status. Proving that someone else could provide the same work on your behalf (and you have the right to provide a substitute in your contract) can have a huge impact on your ability to continue working and being paid through your limited company.

An SDS or status determination statement, is a document that summarises an end hirers IR35 assessment for a specific contractor. It determines whether they fall inside or outside IR35, and therefore how they will be paid and taxed.

From April 2021, it is the end hirers responsibility to assess IR35 status on behalf of you, the contractor. So even if you are a director of your own limited company, you no longer have that responsibility moving forward.