In this article, you will learn about the latest rules on how to vet your substitute. You’ll also find an action list that explains why having a “wingman” isn’t just about covering sickness or holiday — it’s a tax-status insurance policy
Handing over your client work to another freelancer may seem risky on many levels. Hopefully, you may never have to. However, life happens. And having a stand-in freelancer vetted in advance is not only good business sense, but it can also give clients an extra level of confidence when engaging you. Here are some rules you have to consider for making substitution actually work.
If you run your own limited company as a Personal Service Company (PSC) and want to stay “outside IR35,” having a genuine, exercisable right of substitution is one of the strongest pieces of evidence that you’re in business on your own account rather than a disguised employee.
- Get it in the contract first. Confirm your contract genuinely grants a right of substitution before you assume you can send cover
- Vet your substitute properly. Clients will usually only accept a sub if they’re demonstrably qualified to deliver the work at the same standard — don’t just wing it with a mate. It’s actually your PSC that comes into the spotlight here since you are the engager, not the client
- You pay them, not the client. In high-profile IR35 cases, the contractor’s substitution clause wasn’t considered legitimate because the client sourced, arranged and paid them, rather than the contractor. If the client’s money goes anywhere near your substitute, the clause is worthless as tax evidence
- Paper trail everything. Document that your right of substitution has been exercised. You can do this by keeping email threads or other records confirming it with the client because in an IR35 investigation, this can be key evidence
- Reciprocal arrangements are fine. You can cover another contractor’s holiday too, but invoice their business, not their end client
The new, urgent complication (2026 update)
This is the part that changes things significantly and makes relying on previous advice riskier:
From 1 October 2026, the UK’s expanded Right to Work (RTW) scheme means that if a business engages a worker under a contract that allows substitution, it must complete Right to Work checks on that substitute before they start. This is to avoid illegal workers.
Due to this financial risk, corporate legal departments are growing highly risk-averse. As previously reported by The Freelance Informer, to avoid the regulatory burden of verifying substitute workers at intervals of no less than once in any 24 hours of activity, many clients could choose to ban substitution clauses entirely in their contractor agreements.
Penalties for getting this wrong are severe. Civil penalties are rising to £60,000 per illegal worker for repeat offences (starting at £45,000 for a first offence).
Liability now extends up the supply chain, according to Walker Morris. The Home Office may be able to impose a civil penalty on a business further up the contracting chain if the direct employer of the worker cannot be identified or does not pay the civil penalty.
Action list: What to actually do about it
- Don’t let a client quietly strip your substitution clause. If they try to remove it to dodge RTW admin, point out the IR35 tax consequences to you (and the wider engagement risk to them)
- Offer to make their compliance job easy. Suggest OFDIA-registered Digital Verification Service Providers (RTW DVSPs), which can run fast facial-recognition-based digital ID checks on your substitute, or point them to the government’s share code checker (gov.uk)
- Pre-vet and pre-agree your substitute now, not when you’re already booking flights. Write a contract clause with your client specifying exactly how and when a pre-verified substitute would be provided
- Keep the substitute’s pay flowing through your business. Keep the documentation trail. Those fundamentals haven’t changed; they’re just harder to exercise now.
Consider whether outcome-based Statements of Work (SOW) suit you better than a traditional time-and-materials contract, since SOW engagements are increasingly viewed as a safer route to genuine B2B status that sidesteps some of this substitution/immigration tension entirely.
Who this hits hardest, and why
➡️Sole-director PSC contractors in professional/office-based sectors (IT, engineering, consulting, management, marketing) relying on the classic “right of substitution” clause as their main outside-IR35 defence. For many of these, substitution is one of only two or three real status factors they can point to (alongside control and mutuality of obligation), so losing it removes a disproportionate share of their protection.
➡️Contractors working with large corporates and public-sector bodies, whose legal/compliance teams are the most risk-averse and most likely to strip substitution clauses rather than deal with 24-hourly RTW re-checks on a rotating cast of subs.
➡️Contractors who genuinely rely on cover for holidays, illness, or caring responsibilities (rather than those who never actually exercise the clause) — face real practical friction getting a substitute through the door, not just a legal technicality.
Conversely, contractors already on outcome-based SOW arrangements are comparatively insulated, since their outside-IR35 case rests less heavily on a substitution clause and more on deliverables and autonomy.
A Freelance Informer reader offered in an article comment that IR35 case law “looks at the whole working relationship”, and courts have found outside-IR35 status even without substitution being exercised (and dismissed “beautifully written” clauses that were never real in practice).
That makes substitution a strong signal, not a single point of failure. However, given how much cost and hassle a client now faces if they do allow it, the practical risk is that some clients simply won’t offer the option at all, regardless of what case law says.
That’s why you need to reach out ASAP to ideal substitute candidates you can trust in more ways than one. And ask in advance if they are greenlit to work in the UK. If not, they can go to this government link to get started: Prove your right to work to an employer: Overview – GOV.UK
