It still seems unclear. There is some allowance for their approval, but they can't unreasonably deny the substitution (which sounds very vague) "Right of Subst

It still seems unclear. There is some allowance for their approval, but they can't unreasonably deny the substitution (which sounds very vague) "Right of Substitution is fairly clear cut: can you send someone else to do the work. Employees can't do that, so if you can, you are not an employee. However, the client has to have some say in the matter. The usual formula is along the lines of "you may send a substitute subject to the approval of the client, such approval not to be unreasonably withheld"." http://www.freelancesupermarket.com/featured-articles/the-potted-guide-to-ir35.aspx http://www.freelancesupermarket.com/featured-articles/the-po...