IR35 in 2026: the answer depends on the engagement, not your job title

A contractor can be described as a consultant, project manager, developer, engineer or freelancer and still fall within the off-payroll working rules. Conversely, a long-running engagement is not automatically inside IR35. The question is whether, looking at the contract and the relationship actually operated, the individual would have been an employee for tax purposes if engaged directly by the client rather than through an intermediary, normally a personal service company (PSC).

Quick answer: Inside IR35 generally means employment-tax treatment for the relevant engagement under the applicable legislation. Outside IR35 means the hypothetical direct contract is not an employment relationship for tax. Neither conclusion is obtained simply by inserting an “outside IR35” clause into a consultancy agreement. Work through the legal and practical factors, identify who must decide, and keep an evidence file for each assignment.

This guide goes deeper into how to assess the tests, what a Status Determination Statement (SDS) must contain, how the 45-calendar-day disagreement process works, and why a much-discussed company-size threshold change should not automatically be applied to every 2026 contract. It complements, rather than duplicates, Britvex.co.uk’s existing contract-by-contract IR35 article.

Who has to decide IR35 status in the UK?

The first practical step is to identify the end-client and the type of intermediary. For work through a PSC for a public authority or a medium or large private-sector client, the client normally decides status and must take reasonable care; the person responsible for PAYE deductions is determined by the supply chain. For a small private-sector client, the contractor’s intermediary normally remains responsible for applying the older IR35 rules. Arrangements that do not involve an intermediary raise wider employment-status questions but are not automatically within the PSC off-payroll rules.

The identity of the fee-payer or deemed employer also matters: it may be an agency rather than the end-client. HMRC’s off-payroll client guidance provides the starting framework. If there is doubt about the client being small, ask for the appropriate size confirmation rather than relying on a marketing description of the business.

The six employment-status tests: what to examine

1. Control — who directs the work?

Ask who decides what is done, how it is performed, when it must happen and where it is carried out. A client can require a deliverable to meet security, quality, safety and agreed deadline standards without necessarily controlling the individual as an employee. The issue is the degree of direction and oversight. An independent consultant may choose the approach and schedule for an agreed output; a worker placed within a line-management rota may have far less real discretion.

Consider project plans, client messages, approval chains and whether a manager reallocates tasks daily. Merely saying the consultant has “complete autonomy” is weak evidence if internal instructions contradict the contract. Conversely, compulsory site access or confidentiality requirements do not necessarily establish employment control on their own.

2. Personal service and substitution

A genuine right to provide a suitably skilled substitute can matter where the supplier, not the individual, is contracted to deliver the work. But the existence of a substitution clause is not a magic answer. Examine who recruits, pays and controls the substitute; whether the client can reject one for objective reasons; whether substitution would work in practice; and whether the right can realistically be exercised.

A contractual provision permitting substitution only after exceptional permission may offer little real independence. A subcontracting model where the PSC has delivered work through multiple suitably qualified individuals is different. Keep records of substitution arrangements rather than assuming an unused right will settle the status analysis.

3. Mutuality of obligation

The analysis considers what obligations exist between the parties and the nature of the bargain. Being paid for work actually agreed is not, by itself, the same question as whether the client must keep offering further work or the worker must accept future assignments. Do not reduce this complicated factor to “there is no work promised tomorrow, therefore outside IR35.” Consider notice terms, exclusivity, ongoing duties and what happens when a project finishes.

4. Financial risk and opportunity for profit

An independent business may quote a fixed price, correct defective work at its own cost, hold professional indemnity insurance and invest in people, tools or systems. Employees may also face professional responsibility, so the type and reality of the risk matter. A consultant with no chance to profit from efficient delivery and no exposure beyond losing hours presents a different profile from a company accountable for results and remediation.

5. Equipment, organisation and integration

Who provides critical equipment? Does the consultant run a distinct commercial operation with other clients? Are they on the employee hierarchy, responsible for internal management or eligible for staff benefits? Use of a client laptop because of information security may be neutral. The overall operational relationship is more important than any isolated item on this checklist.

6. Intention and the whole picture

Both parties’ genuine intentions can be relevant, but the final answer comes from the rights, obligations and reality of the engagement. Written terms, witness evidence and day-to-day behaviour should agree. A single decisive-looking tick-box rarely replaces a reasoned holistic assessment. This is why an IR35 assessment is not simply an employment contract keyword search.

Worked scenario: two contractors, two different outcomes

Scenario A — outcome-based data migration. A consultancy company agrees to migrate specified data by a fixed milestone, designs its own method, can use approved team members, rectifies defects at its expense, and is not integrated into the client’s management line. These facts could support an outside-IR35 conclusion, although the full hypothetical contract must still be tested.

Scenario B — operational team member. A contractor works fixed shifts, is assigned tasks every morning by the client’s manager, needs personal leave approved, cannot meaningfully substitute another worker and performs duties similar to staff colleagues. The practical pattern may support an inside-IR35 result even if the signed contract says “independent supplier.” Both scenarios are simplified illustrations, not binding determinations.

What is a valid Status Determination Statement (SDS)?

Where the client is the decision-maker under Chapter 10, an SDS must convey its conclusion and reasons to the worker and the person or organisation the client contracts with. The client has to take reasonable care. A generic paragraph which declares every role inside IR35 without examining the individual engagement can fall short. The client should document the evidence and reasoning used, and should re-examine status if material working arrangements change.

From a contractor’s viewpoint, check that the document identifies the relevant engagement, the conclusion, the actual status factors relied on and the contracting chain. An SDS is not the same as a guarantee that HMRC agrees. Request clarification where the reasons do not reflect how the project operates.

How to challenge an inside-IR35 SDS: the 45-day rule

A worker or eligible deemed employer may raise a reasoned disagreement up to the last payment for the services. The client must consider the representations and respond within 45 calendar days of receiving the disagreement. The 45 days is the client’s response deadline, not a universal deadline requiring the worker to submit the challenge within 45 days of receiving an SDS. This distinction is frequently misstated online.

1. Identify the exact SDS, project and reasons you contest.
2. Provide facts: who controls hours, project scope, real substitution rights, financial risk and supporting documents.
3. Submit the disagreement through the client’s stated process and retain delivery evidence.
4. The existing tax treatment continues while the client reconsiders the determination.
5. Obtain a reasoned written response or a replacement SDS with its effective date.

HMRC’s client-led disagreement guidance explains the response requirements and consequences for a client which fails to respond. A dispute should focus on facts and reasoning rather than the contractor’s preferred take-home-pay outcome.

2026 company-size changes: do not use the new limits too early

There has been confusion about the Companies Act company-size thresholds because, for accounting periods starting on or after 6 April 2025, the financial thresholds increased to £15 million turnover and £7.5 million balance sheet total while the 50-employee criterion remained unchanged. The company-size test also involves two consecutive financial years, group rules and the date on which accounts-filing periods ended.

The critical 2026 point: HMRC explains that, for a usual 12-month accounting period, the earliest impact of the transitional rules on a client’s off-payroll position is the 2027/28 tax year. A client cannot safely declare itself small for a 2026 engagement just because its revenue falls below £15 million. Apply the relevant prior-year thresholds, timing rules and group analysis to the engagement. See HMRC Employment Status Manual ESM10006A, updated 7 October 2026.

Inside versus outside IR35: business and cash-flow implications

Where an engagement falls inside Chapter 10, the relevant deemed employer typically accounts for PAYE Income Tax and employee National Insurance on the deemed direct payment and may have employer National Insurance and other employer obligations. This does not automatically convert the contractor into an employee for all employment-rights purposes. The PSC must still keep appropriate company records and avoid double-taxing the payment by accounting for it incorrectly.

Where Chapter 8 applies for a small private-sector client, the intermediary normally has its own deemed-employment-payment calculations and reporting obligations if caught. On an outside-IR35 engagement, the PSC’s ordinary company-tax and director-remuneration rules can apply. But outside IR35 is not the same as “tax-free”, and VAT, payroll and Corporation Tax obligations remain relevant. Seek tailored calculations before comparing contract day rates or dividend plans.

The evidence file that protects a defensible assessment

Keep a copy of each signed contract, schedule, statement of work, SDS and disagreement correspondence. Save information proving actual working practice: messages on deliverable approval, access procedures, project milestones, scope changes, substitution documents where applicable, insurance arrangements, client selection and invoicing. Review the file when an extension alters responsibilities or a contractor begins managing client staff.

For businesses hiring numerous contractors, a consistent register should record client size, legal entity, project scope, responsible decision-maker, SDS issue date, fee-payer, dispute status and review date. Process quality matters as much as the initial tax conclusion.

When to use CEST — and when more review is needed

HMRC provides its Check Employment Status for Tax (CEST) tool. It can be a useful part of an assessment, provided the person using it understands and accurately answers questions about contractual rights and actual working practices. Preserve the questions, inputs, outcome and evidence supporting each answer. A result without supporting factual analysis is a weak audit trail.

For disputed, high-value or complex relationships, independent review of both the contract and actual facts may be sensible. This is especially relevant where a contract contains contradictory substitution terms, the project has shifted from deliverable-based consulting to line management, or multiple agencies are involved.

Common IR35 mistakes to avoid in 2026

• Declaring all consultants with a limited company outside IR35 automatically.
• Assuming work-from-home arrangements or a company laptop prove the outcome.
• Confusing the 45-day client response rule with a 45-day contractor appeal deadline.
• Copying an SDS between roles without reviewing actual duties and working practices.
• Applying the new £15m/£7.5m company-size limits immediately without transitional analysis.
• Treating a contractor’s signed agreement as stronger evidence than the actual arrangements.
• Comparing inside and outside contract rates without considering fee-payer PAYE and employer costs.

Practical IR35 checklist before signing a new contract

1. Identify the end-client, the intermediary and any agencies in the supply chain.
2. Determine which off-payroll chapter applies, including size and timing analysis.
3. Review personal service, control, obligations, business risk and integration.
4. Compare written terms with how delivery will work day to day.
5. Request and retain the SDS if the client is responsible.
6. Model cash flow and company-tax treatment under the appropriate conclusion.
7. Assign an evidence owner and review status whenever the role changes.

How Britvex can support UK contractors and clients

Britvex connects contractor tax services, IR35 advisory and consultant and freelancer accounting with record keeping, payroll and financial planning. The related Britvex.co.uk IR35 guide covers the separate contract-by-contract risk, while this guide provides a practical methodology for tests and challenges.

Need a status review? Contact Britvex with the agreement, statement of work and a description of real working practices. A careful review starts with facts, not a pre-determined “outside” conclusion.