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IR35 is a set of rules which deal with assessing a contractor’s tax status when they work through a limited company.

Generally, IR35 relates to using contractors who work for their own personal service limited company, but it can also apply to people supplying services as part of a partnership or as an individual. The rules set out to determine whether someone should be considered an employee if they weren’t supplying their services via a separate business.

Although IR35 has been around for a while, it remains a confusing issue, so in this post we’ll look at:

What is IR35?

Which organisations need to use IR35?

How does IR35 change your tax status?

How do you know if you are ‘caught’ by IR35?

What are the IR35 tests?

Can you appeal against an IR35 determination?

Summary: IR35 for contractors

IR35 was HMRC’s response to a growing consultancy sector in the UK, in an attempt to crack down on perceived tax avoidance.

The name ‘IR35’ refers to an early press release announcing the Finance Act 2000 which is the legislation that makes it law, and this has become shorthand for the topic as a whole.

Initially, IR35 was used as a way of assessing the tax status of an individual by HMRC. Since 2017, in the case of public bodies, and 2021 for private companies, it has become the employer’s job to assess the taxpayer’s (contractor’s) status.

In essence, IR35 sets out how people should be taxed if they supply services to a customer through a Personal Service Company (PSC), when they would otherwise work as an employee.

Why was IR35 introduced?

It all comes down to the rather uncomfortable topic of tax avoidance. In short, working as an employee means that:

But, if the employee leaves their PAYE position on a Friday, and then starts working in exactly the same role but through their own limited company on the following Monday, it makes it cheaper for employers and more tax-efficient for the employee.

The employer doesn’t need to make employer contributions, they just pay the bill. The worker can pay themselves in a more tax-efficient way through their own limited company. You can see why HMRC would want to shut this loophole down.

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There’s an important point to note before you start worrying about IR35, and it is that the legislation doesn’t apply to all organisations. IR35 regulations don’t apply to small businesses. A small business is one which has:

So, if the business you are contracting with ticks those boxes, then you are clear of IR35 (unless they grow of course). This applies to the whole group though, so if you contract with a small subsidiary of a larger group then you can’t get out of IR35.

Although we are talking primarily about limited companies in the above, the same goes for other types of organisations such as partnerships, charities, and public services.

In the normal course of business, a limited company does work for a client and then sends an invoice for this. The client pays, and the company accounts for its tax at the end of the financial year.

This is what is generally called an ‘outside’ IR35 contract. As the contractor working through a limited company, you might choose to pay yourself a salary through payroll, take dividends, or a combination of the two.

Where a worker would normally just be the client’s employee, but instead they’re working through their own company, the contract is judged to be ‘inside’ or ‘caught by’ IR35, and the position is different.


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The worker must either become an employee with a fixed-term contract and pay PAYE in the normal way, or the client can pay the invoice but make an IR35 deduction.

If it’s the latter, the client deducts income tax and employee National Insurance Contributions (NICs), and pays them over to HMRC on the employee’s behalf along with an employer’s contribution. Just like an employer would.

This is a fundamental change to the tax laws, because until now it has always been the taxpayer’s responsibility to assess their own tax status and ensure that their tax is correctly paid. Under IR35, that burden passes to the employer.

One of the criticisms levelled at IR35 is that assessment of tax status can be difficult given the wide variety of different consultancy arrangements out there. In short, it was impossible to apply a broad-brush approach, although that didn’t stop HMRC from trying!

Under the latest rules, your client must make a judgement as to whether your contract falls into the IR35 orbit.


Known as a ‘determination’, this is a formal way of recording the thought process that goes into assessing your tax status. In general, clients will have made an interim assessment of the role before advertising, so you may well see ads that state whether it is inside or outside IR35.

However, some of the tests relate to the individual. Even though a role might initially look like it is outside IR35, there may be circumstances (if you already work for them, for example) where the determination may change.

Once they make a determination, the client must give you a copy showing what the determination is, and how they arrived at it.

Since the start of IR35, HMRC has tried to devise a simple method of telling whether a role should be inside IR35 or not, and this has met with limited success.

The problem is that contracting is so diverse that a test that seems reasonable for one company completely falls down when tried with another organisation.

The issue is so complex that HMRC regularly loses tribunals based on their own rules! However, there are some tests which give a good general indication, such as those below.

The contract

Exclusive services and length of engagement Is the client justified in expecting the contractor to only work for them? Will the contract last for more than two years?
The intention of the Two Parties Is the intention of the two parties to create an employer/employee relationship?
Mutuality of obligation Does the employer have an obligation to provide more work for the contractor to do and is the contractor obligated to do it?
Right of dismissal Does the client have the right to dismiss the contractor?
Business-like trading Is the contractor acting as a business?


Working practices

Basis of payment Does the person receive a salary or hourly rate?
Provision of equipment Does the client provide all, or a substantial part, of the equipment necessary to do the job?
Personal service and substitution Can the client refuse to accept a substitute contractor?
Control Is the contractor under the direct control of the client manager?
Financial risk Does the client accept the financial risk of the contract?
Part and parcel of the organisation Is the contractor acting like they are part and parcel of the organisation?

Some of these tests are simple and easy to evidence. For example, if you have business stationery printed, maintain your own website, or spend money on advertising for work then that would be business-like.

There’s an over-arching rule that we like to apply here, and it is the duck rule. In other words, if it looks like a duck, walks like a duck, and quacks like a duck – then it probably is a duck!

Of course, the main problem is that this isn’t an exact science, as proven by the fact that HMRC has an unenviable record of losing tribunal cases and appeals. The main message here has to be to take advice, even if you think you’re sure.

Yes, you can although that might not be massively helpful. Once you have the determination then you have the right to appeal. There is a practical note to bear in mind here though.

Let’s first say that organisations must not use a blanket approach. If your client tells you that you’re inside IR35 because they treat all their contractors that way, then this is a clear breach of the rules.

In the real world, contractors can be brought in at short notice to start a role urgently. How enthusiastically will a client go through a determination appeal when there are plenty more candidates around?

This shouldn’t be a consideration for contractors but in truth, we can imagine that clients won’t be keen to go through an appeal process when they can simply appoint someone else. It’s a difficult position for contractors, which sadly doesn’t leave you much room to negotiate.

IR35 was an attempt to cut down on tax avoidance by contractors in a variety of sectors and has now been around in various forms for more than two decades.

It is now the employer’s duty to assess the status of any contractors to ensure that they don’t fall within IR35 and if they do, to pay over tax and NIC contributions.


In short, IR35 is complicated, very complicated. As a result, it’s crucial for contractors and employers alike to make sure they are on the right side of the law.

If you are an employer and you are thinking of using contractors, then you absolutely do need to get help to understand how you should be paying them. If you are a contractor, or you are thinking about going into contracting, then you need to understand the tax rules before you start.

Don’t leave it to chance! Learn more about our online accountancy services for contractors and businesses. Call 020 33554047, and get an instant online quote.

About The Author

Lisa Hinton-Hill

I've worked in the accountancy sector for more than 15 years, and have extensive experience supporting sole traders, partnerships, and SME's. Learn more about Lisa.

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