Understanding Your Legal Status When Self-Employed But Working Exclusively for One Company in the UK

Many people in the UK enjoy the freedom and flexibility of being self-employed. But what happens when you’re technically “self-employed,” yet you find yourself working for just one company, month after month?

This scenario is increasingly common - and it can leave you feeling a little stuck in the middle. Are you genuinely self-employed, or could you actually be classed as an employee? The distinction matters for your rights, your tax position, and your risk if things go wrong.

In this guide, we’ll break down everything you need to know about being self-employed but working for one company in the UK. You’ll learn the risks, what the law says, and proactive steps you can take to stay compliant and protect yourself from day one.

Let’s dive in!

Why Is Your Self-Employed Status So Important?

If you’re “self-employed but working for one company UK,” you might enjoy the perks of choosing your hours and being your own boss. But this setup brings a unique set of legal and tax questions you can’t ignore:

• Employment rights: Are you missing out on benefits like holiday pay, sick leave, or protection from unfair dismissal?
• Tax arrangements: Are you paying the right amount of tax and National Insurance? Or could HMRC say you’re actually employed?
• Misclassification risks: If HMRC or a tribunal decides you’re not genuinely self-employed, both you and the company could face serious penalties or backdated liabilities.
• Contract risks: Without the right agreement in place, you may be left exposed to sudden termination or disputes over payment.

Getting your legal status right from the start isn’t just about following the rules - it’s about protecting your income and avoiding nasty surprises in your work relationship.

What Does It Mean to Be Self-Employed But Working for One Company in the UK?

Let’s clarify the scenario. You may be a freelancer, independent contractor, or sole trader who:

• Has your own UTR (Unique Taxpayer Reference) and submits a Self Assessment tax return;
• Invoices the same company every month, sometimes for years;
• Doesn’t have any other clients or only works for others very occasionally;
• Receives work directions, tasks, or targets from just one manager or business.

This can feel similar to being an employee - but with none of the security. The law looks beyond what your contract says, focusing instead on the real substance of your working relationship. If it walks like a duck and quacks like a duck… you get the idea!

A key thing to remember is HMRC and employment tribunals don’t rely only on contract labels. Even if your agreement calls you an “independent contractor,” courts can still decide you’re essentially an employee or a “worker” (a middle category with some limited rights).

This distinction makes all the difference when it comes to tax, employment law protections, and risks to both parties. That’s why laying proper legal foundations - not just using a template contract - is so important.

How Does the Law Decide If You’re Self-Employed or an Employee?

The UK legal system uses several key tests to ask: are you truly “in business on your own account,” or are you actually someone else’s worker or employee?

Here are the main factors they look at:

• Control: Does the company tell you when, where, and how to work? Or do you set your own schedule and methods?
• Mutuality of obligation: Is the company required to offer work (and are you obliged to accept it), or could you turn it down and walk away?
• Right of substitution: Could you send someone else to do the work, or does the company demand that only you provide the service?
• Financial risk: Do you supply your own tools, take on risk of profit and loss, and invoice as a business?
• Integration: Are you treated as “part of the team,” for instance, getting a staff email address, being listed on the website, or attending staff events?
• Exclusivity: Do you provide services to multiple clients, or just this one company?

The more you look (and act) like an employee, the higher the risk that a court, HMRC, or even the company itself could have to treat you as one. This is especially true if you’re working for just one business (sometimes called the “single client” or “personal service company” issue).

If you want more detail on the differences, check out our guide: Difference Between Employee And Contractor.

Tax Implications: PAYE, Self-Assessment, and IR35 Rules

Tax status is one of the biggest headaches when you’re self-employed but working exclusively for one company in the UK.

Here’s what you need to know:

• Self-employed taxes: If you’re truly self-employed, you’re responsible for Self Assessment, paying Income Tax and National Insurance, and registering for VAT if your turnover is high enough.
• PAYE obligations: If you’re classed as an employee, the company should operate PAYE - deducting tax and NI at source, and providing payslips, Statutory Sick Pay, etc. You would not file as self-employed.
• Worker status: If a tribunal sees you as a “worker,” you may have some extra rights (like holiday pay) but tax is still generally your responsibility - unless the employment relationship is proven.
• IR35 rules: This is a specialist set of tax rules targeting contractors who supply services via intermediaries (like a personal service company) but would otherwise be treated as employees. If you “look and act” like staff, IR35 can apply and force the company to pay tax and NI as if you were an employee.

IR35 rules can be complex and penalties can be severe. If you’re working through your own limited company for a single client, read our in-depth guide: Contractor or Employee: Spotting The Differences & Risks.

What Rights Do You Have (Or Miss Out On)?

Your legal status shapes what protections you have. Here’s how the lines often break down:

• As a genuinely self-employed person: You set your rates, choose when to work, but have no guaranteed hours, no right to holiday or sick pay, redundancy, or unfair dismissal rights.
• If you’re found to be a “worker”: You gain core rights - minimum wage, paid holiday, protection from unlawful deductions, and whistleblower safety - but not full redundancy or unfair dismissal.
• If you’re found to be an employee: You’re entitled to the full package: sick pay, redundancy, unfair dismissal protection, maternity/paternity leave, pension auto-enrolment, and more.

If you have concerns about dismissal, our article on Unfair Dismissal explains your options and protections.

What Are the Key Risks of Misclassification?

If HMRC, a tax audit, or an employment tribunal decides you’ve been misclassified, the consequences can be serious for both you and the company:

• HMRC may demand backdated PAYE taxes, employer’s National Insurance, and even tax penalties and interest from the business (and sometimes you).
• The company or client might be on the hook for backdated holiday pay, minimum wage, and even redundancy payments.
• You could lose your right to claim employment benefits, or have trouble if you’re suddenly let go and seek compensation.
• If a client “lets you go” without notice, or doesn’t pay an invoice, you may have little protection without a clear contract.
• Your eligibility for certain tax reliefs, expenses, or even future unemployment benefits may be affected.

This is why, if you’re working for just one company, it’s essential to be realistic about the nature of your relationship - and put the right documents and processes in place to protect yourself now, before a dispute arises.

How Can You Reduce Your Legal Risks and Stay Compliant?

If you want to stay compliant and shield yourself from misclassification risk, here’s what you should do:

1. Use a Professionally Drafted Contractor Agreement

A clear, tailored contractor agreement is vital for both sides. This agreement will set out:

• The basis of the relationship: that you’re genuinely independent and not under direct control of the company.
• Payment terms, invoicing process, and who provides tools/materials.
• Your right (if any) to substitute another person to perform the work.
• Dispute resolution processes if things go wrong.

Avoid generic templates - your contract must be tailored to your actual working style and risks. If you need help, Sprintlaw can draft an agreement to fit your situation.

2. Work for Multiple Clients (If Possible)

If you provide services to more than one client or company, it’s a strong sign you’re truly self-employed. Even a couple of smaller clients can help reinforce your independence in the eyes of HMRC and tribunals.

But if you do mainly work for one firm, try to at least demonstrate that you have the right to and occasionally do accept other work.

3. Pay Attention to “Mutuality of Obligation”

Your contract should not oblige you to accept all work sent your way, nor should the company be forced to provide a certain amount of work. This flexibility signals a genuine contractor relationship.

4. Maintain Your Own Branding and Business Activities

Operating as a proper business - having a website, business cards, marketing, or even registering a business name - helps strengthen your case as truly self-employed. Check our guide on business structures to see which best suits your needs.

5. Invoice and Manage Your Own Finances

Issue invoices (not just receive “salary” payments), pay your own income tax and National Insurance, and keep your accounts up to date. This all helps show you’re “in business on your own account.” Our walkthrough on keeping business records can help you get organised.

6. Stay Insured

Get the right business insurances - such as professional indemnity, public liability, or others relevant for your field. This is another marker of genuine independence.

7. Review Your Working Arrangements Regularly

If the company is starting to exert more control, or you’re doing the same work as an employee, that’s a warning sign you need new advice. It’s better to adjust early than face a HMRC or tribunal issue later.

What Documents Should You Have in Place?

• Contractor/consultant agreement: Setting terms for your service, boundaries, and responsibilities. Get a bespoke agreement here.
• Invoices and business records: These cover your payment terms, fees, and expenses.
• Business name registration: If you’re trading under a name that isn’t your own, you may need to register it.
• Insurances: Proof of professional or public liability insurance if required by your industry.
• Privacy policies (if handling personal data): For some professions, you’ll need to follow UK GDPR rules - check out our Simple GDPR Guide for Businesses.

Having this paperwork in order doesn’t just protect you legally - it gives peace of mind to your clients, too.

What Should the Company Do to Stay Compliant?

While this article focuses on your perspective, it’s worth noting that companies also risk big penalties if they misclassify workers:

• They should not treat you as an employee for all practical purposes (set working hours, staff perks, etc.) without PAYE.
• They should keep your contract up to date and review arrangements with all regular freelancers annually.
• If in doubt, companies should seek employment law advice - our detailed breakdown will help them too.

What If You’re Still Unsure About Your Status?

It can be tricky to work out where you stand - especially when rules are complex or your situation has changed since your contract was first signed. Some signs you might need tailored legal advice:

• Your client company is pushing you toward exclusive work, set hours, or on-call status.
• You’ve had disputes about payment, termination, or work conditions.
• HMRC or another body has asked about your employment status.
• Your arrangement has slowly become more like a permanent job over time.

If any of these apply, don’t wait for a problem to become a crisis. Speak to an expert about updating your contracts or restructuring your setup for full compliance. Sprintlaw can review your options and help you avoid common pitfalls - just book a contract review with us or get in touch for a chat.

Key Takeaways

• If you’re self-employed but working for one company in the UK, you need to be clear about your real employment status and legal risks.
• Courts and HMRC look beyond your contract wording to your actual working practices - control, mutual obligations, exclusivity, and more.
• Misclassification as an employee or worker can trigger serious tax and legal liabilities for both you and the business.
• Protect yourself with a tailored contractor agreement, keep clear business records, and where possible, work for multiple clients.
• Regularly review your arrangement and get legal advice if your relationship with the company starts looking more like employment than true self-employment.
• Taking these steps early can prevent disputes, tax investigations, and ensure you get the best of both worlds: flexibility and legal protection.

If you want to check your status or need a contract tailored to your business arrangement, our expert team at Sprintlaw UK is here to help. Call us on 08081347754 or email team@sprintlaw.co.uk for a free, no-obligations chat about protecting your freelancing or contracting work.