As specialist interim recruiters, we often are asked by employers to explain the IR35 rules that are relevant to them, We’ve complied an easy reading, short guide to help get familiar with the current IR35 legislation.

IR35 legislation

The IR35 leglislation as introduced by Gordon Brown in the 1999 budget. The term ‘IR35’ stands for the Inland Revenue’s (now known as HMRC) 35th press release.

IR35 rules were introduced to combat tax avoidance via the use of ‘personal service companies’ and targets contractors who have a limited company business structure and who have previously enjoyed some tax efficiency. Otherwise known as ‘disguised employment

To find out more about IR35, what is is and frequently asked questions, view our comprehensive guide ‘What is IR35’.

IR35 for employers in the public sector

  • The IR35 public sector reform was introduced by HMRC in 2017 because of non-compliance within the sector
  • This IR35 public sector reform announced changes in the way IR35 status was determined; all public sector bodies were now responsible for setting the IR35 status of the contractors they engage, whereas previously this burden was on the individual contractor
  • This change was made because public sector bodies are thought to know the role, the responsibility, the project and the tasks better than the external contractor
  • As a consequence, the body is able to better determine the IR35 rules and whether a contractor would be inside or outside IR35
  • Contractors are entitled to know the reasons behind the IR35 determination made by the employer in a Status Determination Statement, which the contractor can dispute

IR35 for employers in the private sector

  • The IR35 private sector reform was introduced by HMRC in April 2021, bringing the public and private sector rules in line with each other
  • The new IR35 private sector rules mean that medium and large businesses now carry IR35 responsibility as well as the fee paying party in the process, which is often recruitment agencies
  • Again, contractors are entitled to know the reasons behind the IR35 determination made by the employer in a Status Determination Statement, which the contractor can dispute if they see fit
  • If you are a candidate working with a recruitment agency, discuss the IR35 rules with your consultant in detail so they can place you at an employer with relevant projects that suit your IR35 status
  • The IR35 private sector legislation states that small businesses are exempt. A small business is one that is defined by the following criteria for 2 years in a row:

1) annual turnover of no more than £10.2 million
2) balance sheet total of no more than £5.1 million

  • If you are a private sector employer, and your business is a small business, you are not required to work out the IR35 status. In this case, the contractor will still be responsible for working out their IR35 determination

Inside IR35 or outside IR35

  • When a contractor is inside IR35, it means the contract falls within the IR35 rules (off-payroll rules) and HMRC sees the contractor as an employee of your business, for tax purposes. This means the contractor must pay income tax through payroll, in the same way as another employee of the business, including full PAYE and National Insurance contributions
  • Being outside IR35 means the contract falls outside of the IR35 rules (off-payroll rules) and HMRC sees the contractor as a self-employed worker. For the employee, this allows for some tax efficiencies when using a combination of salary and dividends. In simple terms, employers pay the contractor an agreed fee for their services, and the contractor maintains responsibility for paying their taxes via self-assessment.

IR35 rules 2024: IR35 inside or outside?

Are a contractor you are looking to engage inside or outside of IR35? 3 categories are considered within IR35 rules 2024 and whether you are an employer or contractor, you’ll need to consider these 3 areas to come to a robust IR35 determination;

IR35 inside or outside: Supervision, direction, control

The first category is supervision, direction, control. This category looks at how much say the employer has over how and when the contractor works or does the contractor have complete freedom over how work is completed. The more control from the business, the more this implies the contractor is an employee of your business and therefore ‘inside IR35’. Other things to consider are whether the contractor will be dedicated only to the agreed task, making a contractor outside IR35 or whether they will be asked to work on other tasks within the business, making them inside IR35.

IR35 inside or outside: Substitution

The second category is substitution. This asks the question – could someone else complete the work instead of the contractor, or does the work need to be specifically completed by them? If you can’t send someone else, you’re likely to be inside IR35.

IR35 inside or outside: Mutuality of obligation

The third category is mutuality of obligation (MOO). If you as an employer offer work, is there an obligation for the contractor to accept? If so, this is a sign that the contractor is working within IR35. A sign of a contractor working outside IR35 is when the contractor is engaged on a project-by-project basis by your business and is allowed to be working across several different companies at the same time. If this is not allowed by you as the employer, this points towards being inside IR35.

IR35 inside or outside: other considerations

Above and beyond the 3 main criteria of supervision, direction and control, substitution and mutuality of obligation, an employer should consider:

  • Equipment – to be outside IR35, a contractor should use their own equipment
  • Financial risk – does the contractor have professional indemnity insurance? If they do, this points to being outside IR35.
  • Payment – someone who falls outside of IR35 is usually paid on a project-by-project basis rather than a set figure monthly.
  • Company structure – if contractors become so ingrained that they become part of a company’s structure, with people reporting to them for example, this points to employment rather than self-employment
  • How a contractor runs their business – if the contractor has their own premises, websites, employees etc, its likely they will be seen as outside IR35.

How to make an IR35 assessment

If you are an employer and need a step by step guide to making an IR35 assessment for your business, read our guide below. Alternatively contact us to discuss your hiring needs and we can help you through the assessment process.

IR35 deemed payment

  • If the contractor is in the private sector and the IR35 rules apply, the intermediary will need to calculate the deemed employment payment
  • The IR35 deemed payment is the amount deemed to be the income of the worker, once deductions and employer National Insurance contributions have been removed
  • The government have complied a Deemed Employment payment calculator to help calculate IR35 deemed payments

IR35 rules 2024: liability

  • If a ‘outside IR35’ status determination was incorrect, all income received is classified as employment income. Any liability plus interest must be owed back to the HMRC and a penalty fine may also be incurred
  • Under the off-payroll rules, this liability sits with the fee-payer should every party of the engagement have met their obligations


There is currently some ambiguity around IR35 rules in 2024, therefore it is advised to look thoroughly at HMRC and Government resources around IR35 topics. We have a specialist interim and contract recruitment team in-house who can help both candidates and employers to understand and navigate the rules as required.

If you need to hire for a interim position, contact us today and we can help get you started on the hiring process.

Further reading for IR35 contractors:

Ir35 Rules Tax Calculation