Five years on from the private sector reforms, IR35 is no longer the scary new rule it once was. It’s now part of the everyday cost of hiring contractors in the UK. What’s changed is the level of HMRC scrutiny and the quality of the tooling available to get determinations right. This 2026 guide is written for hiring managers in IT and tech, financial services and engineering who use contractors to flex their teams, and for the contractors who work with them through our temporary recruitment service.
What IR35 actually is in 2026
IR35, formally known as the off-payroll working rules, is the way HMRC ensures that contractors who work like employees pay roughly the same tax as employees. The legislation hasn’t fundamentally changed since the 2021 private sector reform. What has changed is the volume of cases coming through the First-tier Tribunal and the maturity of HMRC’s Check Employment Status for Tax (CEST) tool.
If you’re a medium or large business engaging a contractor through a personal service company, you are responsible for the IR35 status determination. You issue a Status Determination Statement (SDS) before the work begins, and the fee-payer in the chain operates PAYE if the engagement is inside IR35. Small businesses, as defined by the Companies Act 2006, remain outside the off-payroll rules and the contractor takes responsibility instead.
Our IT and tech consultants see this every day. The contractor market is healthy, rates have firmed up since 2023, and businesses that handle status determinations well are still attracting strong technical talent on short contracts.
Getting status determinations right
Use CEST as a starting point, not as the final word. HMRC stands behind a CEST result if the answers are accurate and the working practices match. The bigger risks are control, substitution and mutuality of obligation — the three classic tests. A contractor who follows the same shift pattern, uses the same equipment and reports to the same manager as employees will struggle to claim outside-IR35 status, no matter how the contract is drafted.
Document the determination properly. The Status Determination Statement must be in writing, given to the worker and any agency in the chain, and supported by reasoning. Keep a copy on file. HMRC’s off-payroll communication resources include sample templates that cover the basics.
Review determinations when working practices change. A contractor brought in for a six-week project who then extends into business-as-usual support is exactly the kind of engagement that flips status mid-contract. Diary a review every quarter, or at the end of each contract extension.
Inside or outside? A practical comparison
An inside-IR35 engagement is taxed at source like employment. The contractor receives a net rate after PAYE and National Insurance, and the fee-payer (often the agency) handles the deductions. Many contractors accept inside-IR35 work happily for shorter assignments, defined deliverables, or when they want to focus on the technical work without administrative overhead.
An outside-IR35 engagement is taxed as self-employment through the contractor’s personal service company. The contractor takes responsibility for their own taxes and gains the flexibility of choosing how they take their income. This is best suited to genuinely independent work — defined deliverables, the right of substitution, and a contractor who works for multiple clients.
Some of our financial services clients run a hybrid model: short-term project work outside IR35, business-as-usual support inside IR35. Done properly, this gives the business clarity and gives the contractor a fair choice.
How NTR supports compliant contractor hiring
We act as the fee-payer for thousands of contractor placements every year, primarily in IT and tech, aerospace and finance. We provide the Status Determination Statement workflow, integrate with our clients’ procurement systems, and operate PAYE correctly for inside-IR35 engagements. Our REC and APSCo accreditations require us to handle IR35 carefully, and we have insurance cover in place if a determination is later challenged.
Frequently Asked Questions
Who decides whether a contract is inside or outside IR35?
If you’re a medium or large business engaging a contractor, you make the determination. You issue a Status Determination Statement before the work starts. For small businesses, as defined by the Companies Act 2006, the contractor’s own company decides. The agency in the middle of the chain typically pays the worker either way.
What’s the penalty for getting IR35 wrong?
If HMRC challenges a determination and wins, the fee-payer is liable for the unpaid tax, interest and potential penalties. Penalties can be up to 100% of the tax owed in cases of deliberate non-compliance. Good documentation and reasonable care are your best defence.
Can a contractor refuse an inside-IR35 determination?
A contractor cannot force you to change the status, but they can decline the work or appeal through the formal disagreement process you must offer. If they appeal, you have 45 days to respond in writing with your reasoning. Many disagreements are resolved by clarifying the working practices rather than changing the status.
Does IR35 apply to overseas contractors?
If the work is performed in the UK or for a UK client, IR35 can apply. The rules around international contractors are complex and depend on tax treaties. HMRC guidance covers the most common scenarios. Always seek specific advice for non-UK contractors before issuing an SDS.
How long should a contractor stay in one role before IR35 risk rises?
There’s no fixed time limit. What matters is the working practices. A two-year contract with clear deliverables, real substitution rights and genuine independence can be outside IR35. A six-month contract that looks identical to an employee’s role is usually inside. Review the engagement, not the calendar.
Can NTR handle IR35 status determinations for our business?
We work alongside our clients on status determinations. We can recommend approaches, share the CEST output, and act as the fee-payer for inside-IR35 engagements. The final determination must be made by the end client under the legislation, but we make the process straightforward.
IR35 isn’t a problem to be solved — it’s a process to be managed. With the right contracts, regular reviews and an experienced agency handling the fee-payer mechanics, hiring contractors in 2026 is just as straightforward as it was before the reforms. Talk to our team if you’d like a second opinion on a current engagement.
Connecting Talent with Opportunity / National Temping Recruitment / https://nationaltemps.co.uk / 0333 772 9824 / info@nationaltemps.co.uk
