Why the Fee-Payer Role Is a Compliance Flashpoint

Since the IR35 off-payroll working reforms came into effect for the private sector in April 2021, the concept of the fee-payer has moved from a technical tax term to a central operational reality for UK staffing agencies. The fee-payer is the party in the labour supply chain that pays the worker's personal service company (PSC) or umbrella company directly. When a contract is determined to be inside IR35 by the end client (the engager), the fee-payer must operate PAYE and National Insurance deductions before making payment. Failing to do so creates a tax withholding liability that HMRC can pursue directly against the fee-payer.

For agencies operating in the UK contractor market, being the fee-payer is not optional: if you are paying the contractor's PSC, you are the fee-payer. The liability is structural, not contractual. You cannot outsource it away through terms of business. Understanding it is a prerequisite for operating in this market.

How the Fee-Payer Role Works

In the typical IR35 supply chain, the end client (engager) makes an IR35 status determination and issues a Status Determination Statement. If the engagement is inside IR35, the tax and NIC deductions must be made by the party directly above the PSC in the payment chain. In a standard agency arrangement, that is the staffing agency. If the agency pays an umbrella company, which in turn pays the contractor, then the umbrella company becomes the fee-payer for that specific payment, though the agency remains responsible for ensuring the umbrella is operating correctly.

The fee-payer calculates the deemed payment: the gross payment to the PSC, reduced by the employer NICs and apprenticeship levy that the PSC would have paid if the worker were an employee, with income tax and employee NICs then deducted from the net amount before payment is made to the PSC. This is a more complex calculation than standard payroll and requires payroll systems that support the deemed payment methodology.

The fee-payer also bears the liability if the engager's SDS determination is wrong and HMRC later determines it should have been inside IR35. While primary liability rests with the engager if they failed to take reasonable care, the fee-payer may face secondary liability in certain circumstances, particularly if they failed to challenge a determination they had reason to believe was incorrect. This creates an incentive for agencies to review client SDSs critically rather than simply accepting them without question.

Consider a technology staffing agency paying a software developer's PSC £8,000 per month. The engager issues an inside-IR35 SDS. The agency must now calculate the deemed payment, deduct PAYE and employee NICs, account for employer NICs on top of the gross fee, and remit the taxes to HMRC via RTI. The PSC receives a net payment after deductions. The agency invoices the end client for the gross amount plus employer NICs, which increases the cost to the client compared to an outside-IR35 engagement.

Fee-Payer vs Engager

The engager is the end client who determines IR35 status. The fee-payer is the party who pays the PSC and who is responsible for deducting and remitting tax on inside-IR35 contracts. They are distinct roles, though a direct engagement with no agency in the chain means the client is both engager and fee-payer simultaneously. In multi-tier supply chains with sub-agencies or umbrella companies, identifying the correct fee-payer requires mapping the actual payment flows, not just the commercial relationships.

Fee-Payer in Practice

A financial services staffing agency supplies eight contractors through their PSCs to a banking client. Following the 2021 reforms, the bank issues SDSs determining five contractors as inside IR35 and three as outside. The agency's payroll team sets up deemed payment calculations for the five inside-IR35 contractors, registers them on RTI, and processes the first month's payments with PAYE and NIC deductions. The three outside-IR35 contractors continue to be paid gross to their PSCs as before. The agency updates its terms of business with the bank to confirm the fee-payer obligations and documents the SDS receipts in case of HMRC enquiry.