IR35 legislation has placed significant responsibility on UK end clients that engage contractors through consultancy agreements. Since the off-payroll working reforms, end clients must assess whether contractors are genuinely self-employed or should be treated as employees for tax purposes. Consultancy agreements play a central role in this process, but they must be supported by accurate IR35 checks and aligned working practices.

This blog outlines best practices for end clients when carrying out IR35 checks on consultancy agreements, helping organisations meet HMRC requirements and reduce compliance risk.

Understanding the Role of Consultancy Agreements in IR35

A consultancy agreement sets out the contractual relationship between the end client and the contractor’s intermediary, usually a limited company. HMRC uses these agreements as a key source of evidence when assessing IR35 status.

However, contracts alone are not enough. End clients must ensure consultancy agreements accurately reflect the reality of the working arrangement.

Legal Responsibility of End Clients

In the UK private and public sectors, medium and large end clients are responsible for determining IR35 status. This includes reviewing consultancy agreements and issuing a Status Determination Statement.

Failing to carry out proper IR35 checks can transfer tax liability directly to the end client.

Taking Reasonable Care in IR35 Checks

HMRC requires end clients to demonstrate reasonable care when assessing IR35 status. This means relying on accurate information, structured processes, and informed decision-making.

Best practice involves conducting detailed IR35 checks rather than relying on generic or template consultancy agreements.

Reviewing Key IR35 Clauses in Consultancy Agreements

Certain clauses are critical in IR35 assessments. These include control, substitution, and mutuality of obligation.

End clients should ensure consultancy agreements clearly define these elements in a way that reflects genuine independent working arrangements where applicable.

Aligning Consultancy Agreements with Working Practices

One of the most common compliance failures occurs when consultancy agreements do not match actual working practices. HMRC places greater emphasis on reality than on written terms.

Best practice involves reviewing how contractors work day-to-day and ensuring consultancy agreements accurately reflect this.

Avoiding Blanket IR35 Determinations

HMRC discourages blanket IR35 decisions that apply the same status to multiple contractors without individual assessment.

Each consultancy agreement should be reviewed independently, with IR35 checks tailored to the specific role and working arrangement.

Using HMRC Tools Appropriately

The HMRC CEST tool can support IR35 assessments but should not be used in isolation. It may not capture all relevant nuances of consultancy agreements.

End clients should combine CEST outcomes with professional IR35 checks to ensure decisions are robust and defensible.

Issuing Clear Status Determination Statements

End clients must issue a Status Determination Statement that explains the IR35 decision and reasoning. This statement must be shared with the contractor and any agency involved.

Well-documented IR35 checks support clear and compliant statements.

Managing Contractor Challenges and Disputes

Contractors have the right to challenge IR35 determinations. End clients must respond to challenges within a set timeframe.

Having well-structured IR35 checks and clear consultancy agreements makes dispute resolution faster and more effective.

Record Keeping and Audit Readiness

HMRC may request evidence of IR35 assessments during audits. End clients must keep records of consultancy agreements, IR35 checks, and decision-making processes.

Organised documentation demonstrates compliance and reduces audit risk.

Understanding Financial Risks of Non-Compliance

If IR35 checks are incorrect or consultancy agreements are poorly drafted, end clients may face backdated tax bills, interest, and penalties.

Best practices in IR35 checks significantly reduce financial exposure.

Supply Chain Communication

End clients often engage contractors through recruitment agencies. Clear communication of IR35 determinations across the supply chain is essential.

Consultancy agreements and IR35 checks should be shared transparently to ensure consistent compliance.

Regular Reviews of Consultancy Agreements

Roles and working practices evolve over time. Consultancy agreements should be reviewed regularly to ensure they remain accurate.

Ongoing IR35 checks help maintain compliance as circumstances change.

Staying Updated with IR35 Case Law

IR35 decisions are influenced by case law as well as HMRC guidance. End clients must stay informed of legal developments.

Professional IR35 checks incorporate current case law into assessments.

The Role of The Infinity Group in IR35 Consultancy Agreement Checks

The Infinity Group provides professional IR35 checks for consultancy agreements, supporting UK end clients with accurate assessments and clear reporting.

Their services help ensure consultancy agreements align with working practices and HMRC expectations.

Reducing Internal Administrative Burden

Managing IR35 compliance internally can be resource-intensive. Professional support reduces administrative workload for HR and finance teams.

This allows end clients to focus on operational priorities.

Protecting Business Reputation

IR35 compliance failures can damage relationships with contractors and regulators. Best practices in consultancy agreement IR35 checks demonstrate responsible governance.

This strengthens trust and professional credibility.

Building a Sustainable Compliance Framework

IR35 checks should be part of a broader compliance strategy. Standardised processes and regular reviews support long-term compliance.

Professional support ensures consistency and reliability.

Conclusion

Consultancy agreement IR35 checks are a critical responsibility for UK end clients. By following best practices, including accurate contract reviews, aligned working practices, and thorough documentation, organisations can meet HMRC requirements and reduce risk.

Working with experienced providers such as The Infinity Group enables end clients to manage IR35 compliance confidently, protect their finances, and maintain strong contractor relationships in an increasingly regulated environment.