How to Protect Your IR35 Position Before a Contract Starts

Once a contract has begun, most of the factors that decide IR35 status are already in place. That’s why the best time to protect your position is before you sign.

The end client carries the tax liability if an assessment is wrong, but you still have a stake in the outcome. If a contract is classed as inside IR35 when it could fairly be outside, your take-home pay and flexibility are affected. You can’t control the final decision, but you can influence how the role is assessed and present evidence that you’re operating as a genuine business.

Taking a few simple steps early can help you avoid being misclassified and give clients confidence that their assessment is correct.

• The tax liability sits with the client, but the financial impact sits with you
• The best time to influence IR35 status is before signing
• Shape contracts around deliverables, not attendance
• Confirm who issues the SDS and how assessments are made
• Keep evidence of independence from day one
• If you disagree with a determination, use the formal SDS dispute process – clients must respond within 45 days
• Use a specialist accountant to manage mixed inside/outside income and stay organised

IR35 focuses on how the engagement looks in practice. The three key tests are:

• Control – who decides how, where and when you work
• Substitution – can someone else deliver the service on your behalf
• Mutuality of Obligation (MOO) – is there an ongoing expectation of work

You’re not trying to “game” the system. You’re making sure your engagement reflects genuine independence, not disguised employment.

Ask early who will issue the Status Determination Statement (SDS) – the end client or the agency.

Clarify their assessment process, timelines and what evidence they’ll use. Knowing this upfront helps you prepare and reduces surprises later.

Frame the work around projects or outcomes. Replacing phrases such as “40 hours per week” with “delivery of X project by Y date” makes it clear you’re being paid for results, not attendance.

Whenever possible, request a Statement of Work rather than a job description.

Ask to define how the work is carried out. A true contractor chooses tools, methods and schedule – provided the result meets agreed deliverables.

Avoid wording that locks you into fixed hours, required meetings, daily supervision or client approval for every decision.

If substitution is practical, ensure the right is written into the contract and the client accepts it in principle.

Also confirm whether you’ll use your own equipment or systems. Using your own supplies is another indication that you are genuinely independent.

Small wording changes can alter perception. Check for terms such as employee, manager, or reports to, which imply employment.

Instead, use business-to-business terminology like contractor, consultant, or supplier.

A specialist contract reviewer can highlight risk clauses and suggest neutral alternatives.

At SG Accounting, we can refer you to one of our trusted insurance partners for pre-contract checks to ensure terms align with your working reality.

Save emails confirming project deliverables, invoices and any agreed scope changes.

• Maintain professional indemnity and public liability insurance
• Keep a live business website or professional profile that markets your services
• Register for VAT, where appropriate, to signal that you operate as a real trading business

Each element reinforces that you’re running an independent company and not just filling a temporary staff post.

Handling company accounts, VAT, PAYE income and mixed IR35 statuses in the same tax year can quickly become complex. That’s why many contractors choose to use a specialist accountant who understands the contracting landscape.

An accountant can:

• Keep your Limited Company compliant, even when you take inside IR35 roles
• Track which income is company revenue, and which is PAYE
• Plan your tax efficiently across the year

If you already have both accounting and umbrella needs, using the same provider (as we offer at SG Accounting) makes life simpler.
It means one point of contact, consistent records and joined-up support no matter how your roles are classified.

Some warning signs suggest a role may have already been marked inside IR35 without proper assessment:

• The client refuses to issue an SDS or says, “we treat everyone as inside”
• The contract describes fixed hours, supervision or approval processes
• You’re offered staff perks such as holiday pay, bonuses or company equipment
• You’re asked to start work before any assessment or written agreement is complete
• Job titles use internal labels like “Contract Manager” or “Temporary Employee”

Politely highlighting these issues can encourage a fair, individual review – something HMRC requires of all clients.

Clients are often cautious because they carry the compliance and tax risk. When you ask questions about deliverables, autonomy or equipment, frame them as helping the client stay compliant.

Mention that HMRC requires clients to assess each engagement individually and that clear documentation protects everyone.

Showing that you understand their obligations builds trust and positions you as a low-risk professional partner.

Sometimes you’ll discover the IR35 status has already been decided before you engage with the agency or client.
If you believe an inside IR35 determination is wrong, you can raise a formal disagreement under the off-payroll working rules.

Here’s how:

1. Request the SDS if you haven’t received it – you’re legally entitled to a copy
2. Ask for reasoning – understanding why the client reached that view helps you respond factually
3. Prepare your challenge – reference evidence such as autonomy, deliverables, substitution rights or similar contracts assessed outside IR35
4. Submit your disagreement in writing – keep it professional, concise and unemotional
5. Wait for a response – the client must reply within 45 days, either confirming or changing their decision

Even if the outcome doesn’t change, you’ve ensured the client meets their obligation to carry out individual, reasoned assessments rather than blanket decisions.

Even if one engagement ends up inside IR35 and you decide to use an umbrella company instead of your limited company, keep your company ready for outside opportunities

Maintain good records, stay up to date on legislation, and continue presenting yourself as a professional business.

Being prepared lets you move smoothly between different types of contracts as opportunities arise.

Protecting your IR35 position starts long before the first invoice.

By defining scope, maintaining independence and understanding the determination process, you can minimise the risk of being placed inside IR35 unnecessarily.

At SG Accounting, we help contractors to navigate both inside and outside IR35 roles when it comes to their accounts.

If you’d like a contract check or guidance on how to approach a client’s IR35 decision, get in touch with our team today.

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