A Contractor Engagement Letter (also known as an Independent Contractor Agreement or Freelance Contract) is a written contract between a business (the client or engager) and an individual or company providing services on a self-employed basis (the contractor) in England and Wales. It sets out the commercial terms of the engagement, including the services to be provided, the fee payable, the duration of the engagement, intellectual property ownership, confidentiality obligations, and the notice required to terminate.

In England and Wales, the key legal distinction between a contractor and an employee or worker is one of the most commercially important questions in employment law. A contractor engaged on a genuine business-to-business basis is not entitled to the statutory employment rights that protect employees and workers — including unfair dismissal protection, statutory sick pay, statutory holiday pay, pension auto-enrolment, and the National Minimum Wage. This distinction can represent a significant cost saving for businesses but carries significant legal and tax risk if the arrangement is not genuine.

The IR35 off-payroll working rules (Chapter 10, Part 2 of the Income Tax (Earnings and Pensions) Act 2003) are the principal mechanism through which HMRC challenges arrangements where an individual who is treated as self-employed for commercial purposes is, in substance, in an employment relationship with the client. Since April 2021, medium and large-sized businesses in the private sector have been responsible for making a Status Determination Statement (SDS) assessment of each contractor engagement. If the engagement is determined to be 'inside IR35', the client must operate PAYE on payments made to the contractor, treating them as a deemed employee for tax purposes.

A well-drafted contractor engagement letter helps to document the genuine self-employment nature of the arrangement by explicitly including provisions that are inconsistent with employment — most importantly, the right of substitution (the contractor's right to send a substitute in their place), the absence of mutuality of obligation (no obligation on the client to offer work or on the contractor to accept it), and the contractor's control over how and where they perform the services. These provisions do not guarantee a particular IR35 outcome, but they provide contemporaneous evidence of the parties' intentions and the actual nature of the arrangement.

This Contractor Engagement Letter template complies with the laws of England and Wales, including the Late Payment of Commercial Debts (Interest) Act 1998, the UK GDPR and Data Protection Act 2018, the Contracts (Rights of Third Parties) Act 1999, and the Copyright, Designs and Patents Act 1988.

A Contractor Engagement Letter is needed whenever a business in England and Wales engages an individual or company to provide services on a self-employed, freelance, or consultancy basis — rather than recruiting them as an employee or worker. Without a written engagement letter, the terms of the arrangement are unclear, disputes about fees, deliverables, and intellectual property are difficult to resolve, and the business has no documentary evidence of the key IR35 indicators that support a genuine self-employment position.

A contractor engagement letter is particularly important in the following situations. First, when engaging a specialist or technical contractor — such as a software developer, graphic designer, marketing consultant, or financial adviser — who provides highly skilled services on a project basis. These engagements typically involve a clearly defined output (a piece of software, a marketing strategy, a financial report) that is more consistent with a genuine commercial contract than with the ongoing personal service that characterises employment.

Second, when engaging a contractor via their personal service company (PSC). Where the contractor operates through a limited company, the engagement is with the PSC rather than the individual, and a written contract between the client and the PSC is essential. The PSC invoices the client for its services, and the individual extracts value from the PSC through salary and dividends. This structure is a primary target of the IR35 rules.

Third, when the contractor will have access to the client's confidential information, clients, or systems. A written contract is the only effective mechanism for imposing binding confidentiality and data protection obligations on the contractor, and for ensuring that the client retains ownership of any intellectual property created during the engagement.

Fourth, when the engagement involves a significant financial commitment. A written contract is essential to define the scope of work, the agreed fee, the payment terms, and the grounds on which either party may terminate the engagement without penalty. Without these terms in writing, disputes about what was agreed can be costly and time-consuming to resolve.

Finally, a written contractor engagement letter is best practice for all contractor engagements, regardless of value, as evidence of the IR35 factors and of the commercial terms agreed between the parties.

A well-drafted Contractor Engagement Letter for England and Wales should cover all of the following key elements.

The parties clause identifies the client and the contractor (whether an individual or a personal service company) with their full legal names and addresses. Where the contractor operates via a PSC, the engagement should be with the PSC, not the individual.

The services clause describes in detail the services the contractor is engaged to provide, together with key deliverables and milestones. A specific and output-focused description of services is one of the strongest indicators of a genuine commercial contract rather than a disguised employment relationship for IR35 purposes.

The duration clause specifies the start and end dates of the engagement, and confirms that there is no guaranteed minimum volume of work — an absence of mutuality of obligation, which is a fundamental indicator of self-employment.

The fees clause specifies the rate of pay (day rate, hourly rate, or fixed project fee), the invoice frequency, the payment period, and the consequences of late payment under the Late Payment of Commercial Debts (Interest) Act 1998. It should also address VAT, which is chargeable at the standard rate on the supply of services by VAT-registered contractors.

The right of substitution clause — if included — is one of the most important IR35 indicators. It provides that the contractor has the right to arrange for a suitably qualified substitute to perform the services in their place, and that the contractor remains responsible for the quality of the services delivered by any substitute.

The tax clause addresses the contractor's responsibility for their own income tax and National Insurance, and explains the IR35 framework and the client's obligation to carry out a Status Determination Statement assessment.

The intellectual property clause assigns ownership of all work created by the contractor during the engagement to the client (or leaves it with the contractor, depending on the commercial arrangement agreed), and grants the client a licence to use any background IP incorporated into the deliverables.

The confidentiality clause imposes binding obligations on the contractor not to disclose the client's confidential information during or after the engagement, and addresses the contractor's data protection obligations under the UK GDPR.

The termination clause provides for termination on notice in ordinary circumstances and immediate termination for cause, and defines the parties' obligations on termination — including the return of materials and transition assistance.

The limitation of liability clause caps the contractor's liability to the client and excludes indirect and consequential loss, providing commercial certainty for both parties.