IR35 compliance best practice | IR35 Shield

All the services and software your business needs for IR35 compliance

Get total confidence in your IR35 status with expert audits, contractor assessments, and case law-backed tools. Reduce risk, meet your off-payroll obligations, and stay compliant with ease.

Get help with IR35 audits, status determinations, and contract reviews.
Reduce the risk of HMRC penalties with expert IR35 guidance.

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Petrofac

IR35 Shield ensures our assessment process is robust and compliant. The added benefit of Monitoring gives us peace of mind that potential tax risks arising during contracts are easily identified and resolved.

Drew Horrocks

Head of UK TA Operations - Petrofac

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Ensure total compliance with all the right IR35 processes

We believe a robust IR35 compliance process should be detailed yet easy to manage, closely follow IR35 status case law, and crucially, be frictionless to implement.

Our unique blend of exceptional technology, protected by a team of proven experts, will safeguard your business now and in the future.

The right IR35 processes

What is IR35 and why should it matter to your business?

IR35 is UK tax legislation designed to identify contractors who operate as disguised employees. If your private sector business is medium/large and engages contractors, you are responsible for assessing their IR35 status. Incorrect assessments could lead to unpaid taxes, penalties, and time-consuming HMRC checks. Our services can reduce your risk by helping you assess IR35 status accurately for every contract and working arrangement.

Our IR35 Services

We provide everything your business needs to stay compliant with IR35.

IR35 Status Determinations (SDSs)

Get consistent, case law-backed IR35 status determinations using our automated assessment software. Designed for medium and large businesses, our tools provide fast, accurate results with clear reasoning to support compliance decisions.

Contract Reviews

The written contract plays a critical role in determining IR35 status. Poorly worded contracts can weaken your position if HMRC challenges a determination. We review your contracts for IR35 risk and help ensure they support a strong, compliant position.

IR35 Audits

Our audit process checks your contracts, status decisions, and working practices to identify gaps before HMRC does. Use it to strengthen your compliance process and prepare for potential investigations or internal reviews.

Defence against an enquiry

If HMRC opens an enquiry, our experts will manage your defence for you. From reviewing evidence to preparing documentation, we work with your team to protect your business from penalties and disruption.

IR35 Training for Teams

Equip your staff with the knowledge to manage IR35 responsibilities confidently. Our training covers legal obligations, real-world scenarios, and how to spot issues before they escalate.

IR35 Protection

Add an extra layer of confidence with IR35 protection. Our Tax Investigation Service covers up to £200,000 of legal costs so you're not left exposed if your business is investigated.

Frequently Asked Questions (FAQs)

IR35 is UK tax legislation designed to identify contractors who work like employees. The off-payroll rules, introduced into the public sector in 2017 and the private sector in 2021, place the responsibility on businesses to assess IR35 status correctly.
In medium and large private sector organisations, the hiring business must determine whether a contractor is inside or outside IR35. This includes reviewing both the contract and the working practices.
Getting an IR35 status wrong can lead to backdated tax liabilities, HMRC penalties, and compliance investigations. Businesses may also face reputational risk and contractor disputes.
An IR35 audit reviews your contracts, status determinations, and working practices. The goal is to spot and fix compliance gaps before HMRC investigates. It gives you a clear picture of your IR35 risk and steps to reduce it.
A contractor working outside IR35 is genuinely self-employed for tax purposes. They’re responsible for their own taxes. Your business isn’t liable for PAYE tax or NI on their earnings.
“Inside IR35” means the contractor is taxed like an employee — you must deduct PAYE tax and NICs. “Outside IR35” means the contractor operates as a legitimate business and is paid gross. Getting this right is critical to avoid non-compliance.
Sometimes we've heard “Outside IR35” being referred to as "Out of IR35". “Outside IR35” means the contractor operates as a legitimate business and is paid gross. Getting this right is critical to avoid non-compliance.
No. HMRC's CEST tool is not mandatory. You can use independent IR35 assessment tools — like IR35 Shield — to meet your obligations. Our software is backed by case law and provides clear, consistent results across your contractor population.

Trust the right team with your IR35 Compliance

An IR35 defence team with proven experience successfully defending enquiries from inception to tax tribunal. The team’s forensic fact-finding methods have been developed from comprehensive technical input, analysis and know-how of the status domain, with the primary aim of seeking early closure.

Chris Leslie

Chris Leslie

Chris Leslie has over 30 years’ legal experience defending clients in disputes with HMRC. His years managing Status Inspectors at HMRC, combined with his specialist qualifications in analytics, give him an in-depth understanding of how to counter the arguments used by HMRC.

Dave Chaplin

Dave Chaplin

Dave Chaplin is the UK's leading IR35 authority. He consults with HMRC and government on IR35 matters, attends tax tribunals to stay current with case law, has authored two definitive IR35 books, and pioneered the first online IR35 status assessment algorithms nearly 20 years ago.

Dave and Chris’ in-depth knowledge of IR35 and off-payroll combines to provide expert defense and guidance for your business. For help with an IR35 audit or compliance check please get in touch with our team.

Loved by our partners and their teams

Don't just take it from us, listen to some of the reasons our partners recommend IR35 Shield.

IR35 Shield saves us time, and its robustness leaves us comfortable in the knowledge that our workers have been assessed properly.

Debbie Chinn

Debbie Chinn

HR Advisor - PGA

IR35 Shield ensures our assessment process is robust and compliant. The added benefit of Monitoring gives us peace of mind that potential tax risks arising during contracts are easily identified and resolved.

Richard Mossman

Drew Horrocks

Head of UK TA Operations - Petrofac

The assessment being weighted fairly across all factors gives us the confidence to reassure our clients that the outcome is correct.

Katherine Miller

Katherine Miller

Head of Legal and Audit - La Fosse

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NEW
IR35 Academy

IR35 training. Proof for HMRC, best practice for your business.

HMRC investigations request proof that you've trained your staff on IR35 and off-payroll. Our online training makes IR35 simple, educates your team and demonstrates your compliance to HMRC.

We've got your back

When HMRC challenge your IR35 compliance, our expert team is here to minimise your stress. With professional fees covered, we'll take care of the entire defence process and help resolve any investigation quickly.

Chat with an expert about our Tax Investigation Service
Tax Investigation Service

Our recent successes

IR35 Case: RALC Consulting v HMRC

The team successfully defended IT Contractor Richard Alcock at First-tier Tribunal, which defeated two barristers representing HMRC Solicitor’s Office. Chris and Dave worked together for 18 months to build the case defence before defending during a four day hearing. They succeeded in countering HMRC’s IR35 Opinion and extended time assessments with the Judge upholding RALC’s appeals.

IR35 Shield Swiftly Closes HMRC IR35 Investigation

When a long-time client of IR35 Shield received notice of an IR35 investigation by HMRC, the company turned to IR35 Shield's compliance experts for representation. Within months, the investigation was closed with no tax bill.

Ongoing enquiries

Dave and Chris are currently managing a range of IR35 enquiries and also offer consulting for businesses to help ensure their procedures and processes achieve defendable positions in light of the new off-payroll working legislation.

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We know the details so you don't have to

We keep our finger on the pulse of IR35. You can trust our advice and guidance is always up to date.

Does IR35 apply to overseas contracts? Explaining the overseas exemptions

The off-payroll rules apply only to contracts where either the client is a UK tax resident or the work is carried out in the UK...

Read more
As a small company, should you assess your contractors IR35 status?

The IR35 reforms that came into effect in April 2021 do not affect small companies. Nonetheless, some small companies...

Read more

Why companies large and small trust IR35 Shield

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IR35 status assessments delivered to our customers. And counting.

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The average recommendation score from our customers.

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The year we built and released the UK's first IR35 status tool.

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Definitive IR35 status results. Inside or outside IR35, no indeterminates.

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Over 20 years of experience at the cutting-edge of IR35.

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Defence cost cover available with our Tax Investigation Service.

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