A Guide to IR35

IR35, also known as ‘intermediaries legislation’, or ‘off-payroll working legislation’, is a tax law which seeks to ensure no tax advantage is gained by disguising employment as self-employment. 

‘Disguised employment’ is where a contractor appears to be working for themselves, but in reality acts like an employee of their client.

If this sounds confusing, you are not alone, the rules which govern when IR35 applies are extremely complex, making it very hard to be compliant with the legislation. HMRC frequently lose IR35 cases at tribunal, which has led to criticisms that even HMRC doesn’t understand the rules.

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How does IR35 work?

IR35 is based on case law, and therefore built upon the outcomes of each individual case. It works on an engagement-by-engagement basis, meaning it looks at the nature of each contract with a client, not at individual companies.

How is IR35 status determined?

It’s complicated, but there is one basic rule to bear in mind: does the engagement look and feel like employment? If it does, it is more likely IR35 will apply. To help the courts understand what ‘looking and feeling like employment’ really means, they have come up with three main factors to consider, and a handful of supplementary ones.

The three main factors are:

Personal service/substitution

Are you required to carry out the work yourself, or you can you send a substitute to do it in your place? Employees cannot send a substitute, so being required to offer personal services points towards IR35 applying.

Supervision, direction, and control

What degree of supervision, direction and control does your client have over what you do? Do they tell you how to do the work? Employees are controlled by their employer, so the existence of control points towards IR35 applying. 

Mutuality of obligation (MOO)

Is your client obliged to offer you work beyond the agreed project, and are you obliged to accept it? Employees and employers have mutual obligations, so the presence of MOO points to IR35 applying.

You’ll need to be able to demonstrate that at least one of these factors does not apply to your contract and working practices to avoid IR35 applying. For example, if you have an unfettered right to send a substitute, IR35 doesn’t apply, regardless of control and MOO.

Supplementary factors

Sometimes it’s not clear whether the factors above apply or not. In these instances, the following may be taken into consideration:

Part and parcel 

How integrated into the client business are you? Are you ‘one of the team’ or is it clear to everyone that you work separately? Separation from the client business is a good indicator that IR35 doesn’t apply.

Use of your own equipment 

Employees use equipment supplied by their employer. Independent contractors use their own equipment. This test doesn’t always work in practice. There are often good reasons – such as safety and security – why an independent contractor would use the client’s equipment.

Financial risk 

If you make a mistake, do you fix it on your own time, or the client’s? Independent contractors would typically be expected to fix it on their own time.

Did you go to the Christmas party?

 This one is sometimes jokingly referred to but there is an important point behind it. Do you attend staff entertainment events, paid for by the client? If so, it could be unhelpful for your IR35 status.

In an IR35 tribunal, the judge will consider all these factors and others to try to determine if, were it not for the existence of your limited company, the relationship would be considered employment. If the judge decides that it would, IR35 will be applied.

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What can I do to comply with IR35?

There are a few simple steps you can take that will dramatically reduce the risk of IR35 being applied to your engagement. The key is to make it clear to all parties that you are not an employee and should not be treated like one. If you have the following in place, it will make it much easier to explain to a client, agency, or indeed HMRC, that IR35 should not apply.

Ensure your compliance...

  • Get a good contract in place making it clear this is a contract for services, not ‘of service’. IPSE has template contracts that have been drafted by Travers Smith specifically to ensure the engagement is deemed ‘outside IR35’.
  • Statement of work. A SOW is often used to define the project you will be working on. The idea is the contractor is released once the project or task has been completed. The contract is designed to provide commitment on the outcome or quality contractor will provide. The existence of a SOW can help to dispel the notion that mutuality of obligation exists – a key factor when determining IR35 status.
  • Fixed price projects – where possible it would be helpful (from an IR35 point of view) to agree milestones within the project and payment instalments on the completion of each milestone. Remember, employees get paid on a monthly or weekly basis – you don’t want to look like an employee in disguise.
  • Get your contract professionally reviewed for IR35. Before you sign a contract, get it reviewed for IR35 by a professional. The review will tell you which clauses to push back on, to ensure you stay the right side of IR35. IPSE provides a contract review service.
  • Get your working practices reviewed. It’s important to have a good ‘IR35 friendly’ contract in place. But HMRC will want to know the working practices match the contract. IPSE offers a working practices review service.


It’s all about putting clear daylight between you and your client’s employees. The clearer it is that you are not a ‘disguised employee’, the better it will be for your IR35 status.

What happens if IR35 applies?

If IR35 applies there is an increased tax liability. Essentially, the government is looking for the tax that would have been paid, had the engagement been deemed employment.

Public sector changes

Since April 2017, in the public sector, clients have had to determine the IR35 status of engagements. Where IR35 is deemed to apply, the fee-payer (the entity in the chain which pays the contractor) must ensure those payments are made via the RTI system – meaning tax is deducted at source, as it is for employees.

IR35 in 2020

From April 2021, IR35 will be brought into the private sector in line with how it applies in the public sector. For more information see our IR35 hub here

Check Employment Status for Tax (CEST)

CEST is an online tool which seeks to help clients determine the IR35 status of an engagement. It is heavily criticised by experts, and only gives an answer in 85 per cent of cases.

HMRC is committed to improving the CEST tool as part of the current ongoing consultation. IPSE believes the CEST tool is fatally flawed and should not be used.

For more information, view IPSE’s IR35 changes guide.

Join the campaign against IR35

The changes to IR35 were a disaster in the public sector in 2017 and they will be even worse when applied to the private sector in 2021. They could affect the livelihoods of hundreds of thousands of contractors. IPSE is campaigning hard against the changes to IR35, pushing the government to halt and fully review them.

We are also raising awareness about what the changes might mean to the self-employed, how they can prepare, and how IPSE can help protect you.

Join our #stopIR35 campaign


This article has been compiled using information available to IPSE on 09/09/2020