Search

How can we help?

Icon

IR35 – Government’s CEST tool produces undetermined outcome

The Government’s CEST tool, designed to help determine whether a worker will be caught by the changes to the off payroll working rules (IR35) was unable to reach a conclusion in 19% of cases checked in the last year.

In data released by HMRC, between 25 November 2019 and 24 November 2020 the CEST tool delivered 975,416 outcomes. Of these outcomes:

  • 505,598 (52%) found the worker fell outside the IR35 rules;
  • 281,099 (29%) found the worker would be inside IR35; and
  • 188,719 (19%) were undetermined.

HMRC note in its comments alongside the data that in ’more finely balanced cases’, the tool will produce an ‘undetermined’ outcome and advises users to refer to their detailed IR35 guidance to make their decision on whether a worker falls within IR35.

281,099 (29%) found the worker would be inside IR35

Responsibility for making these status determinations is due to shift from the worker to the ‘end user’ client on 6 April 2021, but specialists such as Qdos have voiced concerns that the tool still is not ‘up to scratch’ following its update in November 2019 and will leave users without the clarity they need to make these decisions.

There are currently no plans to update the CEST tool further, as HMRC believe adding in the more complex questions needed to reach an outcome in more cases would make ‘increase the burden’ for most people using the tool. They will however publish this data on a quarterly basis going forward, in a bid to improve user confidence in the tool.

Should you have any queries about IR35, including about status determinations, our employment team is on hand to help.

Disclaimer
This information is for guidance purposes only and should not be regarded as a substitute for taking legal advice. Please refer to the full General Notices on our website.

Author profile

About this article

Read, listen and watch our latest insights

Pub
  • 04 December 2025
  • Immigration

UK Immigration: What to expect in 2026 for employers

Join our UK immigration specialists, Ruth Karimatsenga and Monica Mastropasqua, as they explore the key updates and how they affect your business in 2026.

Pub
  • 04 December 2025
  • Corporate and M&A

Autumn Budget 2025 Breakdown: Key takeaways for business buyers and sellers

Join Stuart Mullins and Nicky Goringe Larkin as they delve into the key updates from the Chancellor’s announcement, with a focus on what matters most for businesses looking to buy and sell.

art
  • 03 December 2025
  • Corporate and M&A

Why is carrying out a legal Due Diligence investigation necessary during an proposed acquisition?

Merging with or acquiring another company is a high-stakes endeavour. The purpose, process and common areas of investigation during a M&A transaction.

art
  • 02 December 2025
  • Employment

All I Want for Christmas… Is No Tribunal Claims!

Before the festivities begin, it is worth unwrapping the key risks and understanding how employers can protect their staff, their reputation and their sanity, while still delivering a thoroughly enjoyable evening.

art
  • 01 December 2025
  • Immigration

Government consultation on extending settlement requirements: What employers and migrants need to know

This article summarises the key proposals , groups who will and will not be affected by the extending settlement requirements, and the potential impact for employers, workers and families.

art
  • 28 November 2025
  • Commercial Real Estate

Auction Sales: Key Things to Consider

Buying or selling a property at auction can offer both buyers and sellers unique advantages, but it also comes with potential risks.