IR35 and Contractor Compliance: Why GPS Timesheets Protect Both Sides

Dave is an independent heating engineer. He works for three facilities management companies through his limited company, invoicing monthly based on day rates. He’s been outside IR35 for six years, genuinely self-employed, genuinely in business on his own account. Then HMRC opens an enquiry. They want to see how Dave’s working arrangements actually look in practice. Not what the contract says, what really happens. Who decides when he starts? Who tells him where to go? Does he use his own tools? Can he send a substitute? IR35 GPS timesheets protect everyone.

The answers to these questions determine whether Dave is genuinely self-employed or effectively an employee for tax purposes. And the evidence that supports those answers increasingly comes from digital systems, including GPS timesheets. Because when HMRC asks “does the client control when and where the contractor works?”, a GPS log showing that Dave chose his own start times, selected his own routes and worked at multiple client sites on the same day is powerful evidence of genuine self-employment. Conversely, a GPS log showing that Dave clocked in at 8:00 every morning at the same site, following a schedule set by the client, suggests something closer to employment.

IR35 investigations are increasing in 2026 – HMRC has hired additional compliance officers specifically for the off-payroll rules. For both contractors and hiring businesses, having clear, verifiable evidence of how work is actually performed has never been more important. And GPS timesheets provide exactly that evidence, in both directions.

IR35 GPS timesheets: supporting status

Three IR35 indicators are directly evidenced by GPS timesheet data. Control: does the contractor choose their own hours and location? Mutuality of obligation: is there a pattern of continuous engagement or project-based work with gaps? Right of substitution: does the contractor work at multiple sites, suggesting genuine business independence? GPS logs show all three, objectively, timestamped, and impossible to fabricate after the fact.

For the hiring business, this evidence is equally valuable. Medium and large businesses have been responsible for determining IR35 status since the off-payroll reforms. If HMRC disagrees with your determination, you’re liable for the tax, NI and penalties. Having GPS data that supports your “outside IR35” determination, showing the contractor’s genuine autonomy over when and where they work, is the difference between a successful defence and a six-figure tax bill.

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Protection for both sides

The beauty of GPS-verified timesheets in an IR35 context is that they protect both the contractor and the hirer simultaneously. The contractor gets evidence that they control their own working pattern. The hirer gets evidence that they haven’t exercised undue control. Both get accurate billing data that eliminates disputes over hours worked. It’s the rare compliance tool that makes everyone’s life easier, not harder.

A system like GeoTapp Verifier produces tamper-proof work reports that capture exactly what HMRC wants to see: when work started, where it happened, how long it lasted, and that the data hasn’t been altered after the fact. Whether you’re a contractor building your defence or a hirer documenting your due diligence, the evidence speaks for itself.

There’s a broader trend here that smart contractors are leveraging: the shift from subjective assessments to objective evidence in employment status. HMRC’s approach is becoming increasingly data-driven, and the businesses and contractors who can provide clean, timestamped, geolocated records of working patterns are in the strongest position, regardless of which side of the IR35 line they fall on. The evidence doesn’t argue a case. It states facts. And facts are what tribunals and HMRC investigations ultimately rely on.

Whether you’re a contractor protecting your independence or a hirer managing your supply chain risk, GPS-verified timesheets are the cheapest insurance you can buy against an IR35 investigation that goes wrong.