Contractor vs employee: getting the working relationship paperwork right

Misclassifying a worker is one of the more expensive mistakes an early-stage startup can make. Get it wrong and you could face back-dated tax bills, National Insurance contributions, holiday pay claims, and potential employment tribunal proceedings. The paperwork you put in place matters, but so does the reality of how the working relationship actually operates day to day.

This post walks through the key distinctions, what documents you need, and where founders commonly go wrong.

Why the label on your contract is not the whole story

Many founders assume that writing "independent contractor" at the top of an agreement settles the question. It does not. HMRC and employment tribunals look at the substance of the relationship, not just what the contract says. If someone works exclusively for you, follows your processes, uses your equipment, and cannot send a substitute, the label "contractor" offers little protection.

There are actually three categories of worker status in the UK:

• Employee - the highest level of employment rights, including unfair dismissal protection, statutory sick pay, and maternity or paternity pay
• Worker - a middle category entitled to national minimum wage, holiday pay, and rest breaks, but fewer protections than employees
• Self-employed / independent contractor - responsible for their own tax, generally no statutory employment rights

Getting the category right is the starting point for choosing the right paperwork.

Key factors courts and HMRC look at

When assessing whether someone is genuinely self-employed, the following factors come up repeatedly:

• Substitution - can they send someone else to do the work without your approval?
• Control - do you dictate how, when, and where work is done?
• Mutuality of obligation - are you obliged to offer work, and are they obliged to accept it?
• Integration - are they embedded in your team, attending all-hands meetings, using your email address?
• Financial risk - do they invoice multiple clients, supply their own equipment, and bear the risk of doing the job twice if they get it wrong?

No single factor is decisive. Tribunals look at the overall picture.

What a solid contractor agreement should cover

If you have assessed the relationship and it genuinely is self-employed, your written contract should reflect the reality. A well-drafted contractor agreement typically includes:

• A clear description of the services and deliverables
• Payment terms, including how and when invoices are raised
• A genuine substitution clause (and an intention to actually honour it)
• Confirmation that the contractor supplies their own tools and equipment where relevant
• Intellectual property assignment, making clear that work created belongs to your company on payment
• Confidentiality obligations
• A statement that the contractor is responsible for their own tax and National Insurance
• A right for either party to terminate with reasonable notice

The IP clause deserves particular attention at a startup. Unless your contract explicitly assigns intellectual property to the company, the contractor may retain ownership of code, designs, or copy they create for you. This is a common and painful oversight.

IR35 and off-payroll working

If you engage contractors through their own limited companies, IR35 rules add another layer of complexity. Under the off-payroll working rules, medium and large businesses must assess whether a contractor would be an employee if engaged directly. Small companies (which most startups are) are currently exempt, meaning the responsibility sits with the contractor's personal service company. Even so, it is worth understanding the rules before you scale, because the threshold creeps up.

If you are unsure whether IR35 applies to your situation, speak to an accountant or tax adviser. This is not an area to guess on.

When you should use an employment contract instead

If the working pattern looks like employment in practice, you should use a proper employment contract rather than trying to paper over it with a contractor agreement. The short-term saving is not worth the liability. An employee arrangement means:

• Running payroll via PAYE
• Enrolling them in a pension scheme (auto-enrolment applies from day one for eligible workers)
• Providing a written statement of employment particulars on or before their start date
• Giving them statutory rights from the start, including paid holiday

The written statement requirement

One point founders sometimes miss: employees must receive a written statement of employment particulars on or before their first day. This is a legal requirement under the Employment Rights Act 1996. It is not optional even for a three-month probationary hire.

A quick sense-check before you sign anything

Before issuing either type of agreement, ask yourself honestly:

• Could this person realistically work for three other clients at the same time?
• Would I be comfortable if HMRC reviewed how we actually work together?
• Have I properly assigned any IP they will create?

If you are uncertain about the right classification for a specific arrangement, take advice from an employment solicitor before the relationship starts. It is much easier to structure things correctly from the beginning than to unwind a misclassification later.