Control as an IR35 Factor: What, How, When and Where

Control as an IR35 factor: what, how, when and where you work

Control is one of the core factors HMRC looks at when it comes to employment status, alongside substitution and mutuality of obligation. In practical terms, control is about who decides the work: who decides what needs doing, who decides when it's done, who decides where it's done, and who decides how it's done. The more the client dictates these things, the closer the working arrangement sits to employment. The more the contractor decides them, the closer it sits to a genuine business-to-business relationship.

This article explains what HMRC's own guidance says about control, and how "what, when, where and how" plays out in real contracting scenarios. It does not tell you what your own status is: that depends on the actual facts of your working arrangement and is ultimately a matter for the client's Status Determination Statement (SDS) and, where needed, a specialist review.

Why control matters for employment status

HMRC's Check Employment Status for Tax (CEST) tool asks specifically who decides what work needs to be done, and who decides when, where and how that work is carried out. These questions exist because control is one of the long-standing indicators used by tribunals and by HMRC to assess whether a relationship looks like employment or like self-employment.

Importantly, HMRC's off-payroll working guidance is explicit that there is no single statutory employment test. Instead, status determinations should weigh a range of factors together, including contract terms, substitution rights, and control over the work. Control is never assessed in isolation, and a written contract that says the contractor has full control means little if the day-to-day reality is different.

What: who decides the work itself

The starting point is who decides what work is actually done. In a genuinely self-employed arrangement, a contractor is typically engaged to deliver a defined outcome or project, with the client having limited ongoing say over the detail of how that outcome is reached once the scope is agreed. Where a hirer can freely reassign a worker to different tasks or projects as business needs change, day to day, that points more towards supervision and direction associated with employment.

Where: location control

HMRC's Employment Status Manual sets out several scenarios for location control, including arrangements where the hirer dictates a fixed site, arrangements where the worker chooses their own location, arrangements where the location is effectively set by the nature of the task itself, and mixed arrangements combining these (ESM11080). A hirer insisting on a specific office, desk or site, with no real flexibility, tends to indicate stronger control. A contractor able to choose where they work, provided the deliverable is met, tends to indicate weaker control, which is more consistent with self-employment.

Hybrid and remote working have made this factor more nuanced in recent years, and it is worth remembering that location control is only one strand of the wider control question, not a standalone test.

When: control over working time

Separately, HMRC's guidance on control and timing looks at whether the hirer sets core hours the worker must be present or available, whether the worker is free to decide their own hours, and whether the work is instead structured around agreed deadlines rather than fixed attendance (ESM11075). A contractor who must clock in for set shifts, mirroring employees, looks different from one who is simply given a deadline and left to organise their own time to hit it.

How: supervision and direction over methods

The final strand is control over how the work is done: the degree of supervision, instruction and direction a hirer exercises over the methods, tools and approach used. A contractor engaged for specialist expertise, who is trusted to choose their own methods and is not closely supervised, points away from employment. A worker who is instructed step-by-step, checked on regularly, and given limited discretion over method, points towards it.

There's no single statutory test

HMRC's guidance on making status determinations confirms there is no statutory employment test in the off-payroll rules. Determinations should look at the whole picture, including contract detail, substitution rights, and the four control questions above, rather than any one factor in isolation. It's also worth noting that the general legal definition of "employee" for employment law purposes, under section 230 of the Employment Rights Act 1996, is separate from tax status and turns on whether someone works under a contract of employment. Tax status and employment-rights status can, in practice, diverge.

For questions about employment rights and status more broadly, the relevant regulator is the Fair Work Agency (FWA), rather than this platform.

What this means for contractors

If a listing states the engagement is outside IR35, that is the client's own claim, based on their assessment of the working practices, not a guarantee from this site or from any tool. A CEST result is evidence the client may rely on, but HMRC itself treats CEST outputs as not determinative on their own. An SDS or contract review is evidence provided by the client about their assessment, not independent verification.

If you want to compare how control, substitution and other factors are described across live contracts, you can browse outside-IR35 contracts or check current day-rate benchmarks for context on how roles in your sector are being advertised.

Control is a fact-specific area, and the right approach for any individual engagement depends on the actual working practices, not just the paperwork. If you are unsure how control factors apply to a specific contract, a qualified IR35 contract reviewer or contractor accountant can look at the real detail of the arrangement.

This platform does not determine, verify, or warrant IR35 status; the SDS is the client's legal responsibility. Contractors should take their own advice and consider IR35 insurance.