Many believe that without true intent to execute a substitution in a given engagement, a right of substitution is simply a loophole. Sometimes they'd be right. Sometimes they'd be wrong.

What's critical is what would/could happen in a case where the usual resource is unavailable for a limited period, at a time when a resource being present is critical to maintaining contractual delivery obligations. If the client would source cover from somewhere else for a duration of, say, a couple of weeks (good luck doing that), independently of the contracted limited company, then the right of substitution is likely a loophole and a sham. If, on the other hand, the main resource's limited company, has the capability and would/could, in such a case, provide and pay for an alternate resource, commit to provide a free of charge lead in, and retain responsibility for delivery of their limited company's contractual obligations, the right of substitution is a genuinely available service and legal right. Even if never used. The biggest problem is most contractors DON'T have the demonstrable capability to engage and pay a substitute. Those who have joined 34square, however, absolutely DO.