TL;DR

The deemed employer is the entity HMRC designates as responsible for determining IR35 status and operating PAYE when an off-payroll worker is engaged through an intermediary. Since April 2021, the deemed employer in the private sector is usually the end client — and that shift transferred significant compliance burden from contractors to the organisations that engage them.

How Deemed Employer Status Works

The IR35 off-payroll rules do not operate on the actual contractual employer — they designate a deemed employer based on the structure of the engagement. When a worker provides services through their own limited company (a Personal Service Company or PSC) to a client, HMRC asks: would this person be an employee if the PSC did not exist? If yes, the engagement is inside IR35, and someone in the chain must operate PAYE.

Prior to April 2021 (private sector) and April 2017 (public sector), the PSC was responsible for making that determination and operating PAYE if inside IR35. Contractors routinely concluded they were outside IR35. HMRC concluded they were mostly wrong. The rules were reformed to shift that determination — and the financial liability — to the end client.

Under the current rules, the end client issues a Status Determination Statement (SDS) assessing whether the engagement is inside or outside IR35. If inside, the fee-payer — the entity paying the PSC directly, usually a staffing agency — must deduct income tax and employee National Insurance from the gross fee before paying the PSC. That agency becomes the deemed employer for PAYE purposes.

In a direct engagement (no agency in the chain), the end client is both the client and the fee-payer — they are the deemed employer and must operate PAYE directly.

The Status Determination Statement

The SDS is what formally triggers deemed employer obligations. The end client must issue a written SDS to the PSC and to the fee-payer, setting out their determination and the reasons for it. The reasons requirement is not optional — an SDS without reasons is treated as non-compliant.

The end client must also establish a process for contractors to dispute their SDS. The client has 45 days to respond to a disagreement with a reasoned reply. If the client fails to respond in time or fails to pass the SDS down the chain correctly, the deemed employer status defaults to the end client, regardless of who is actually paying the PSC.

HMRC's Check Employment Status for Tax (CEST) tool can be used to support the determination, though it has been widely criticised for producing inaccurate results in borderline cases. Case law — including Atholl House, RALC Consulting, and others — has developed the test considerably beyond what CEST captures.

Why It Matters for Recruitment

Staffing agencies sit in the middle of most IR35 chains, which makes them the fee-payer and therefore responsible for operating PAYE when an engagement is inside IR35. The agency does not determine IR35 status — that is the end client's job — but the agency bears the payroll tax obligation once status is set.

For agencies, this means: ensuring they receive a compliant SDS before processing any PSC invoice; withholding income tax and employee NIC from gross fees for inside IR35 engagements; paying employer NIC on top of those gross fees (an additional 13.8% cost that often lands on the agency's margin or gets passed back to the client); and maintaining records sufficient to demonstrate compliance in an HMRC investigation.

For end clients, the reform created a direct financial exposure that did not previously exist. Organisations that get status determinations wrong can be assessed for the unpaid PAYE and NIC — a liability that applies even if they believed they were following the rules correctly.

In Practice

A media company engages a video production specialist through a staffing agency. The specialist works through a PSC. The media company issues an SDS finding the engagement inside IR35: the specialist works on site, uses company equipment, and cannot substitute. The agency receives the SDS, adds the specialist to its payroll-equivalent system, deducts income tax and employee NIC from the £600/day rate before paying the PSC, and pays employer NIC of £82.80/day on top of the gross fee. The agency is the deemed employer for PAYE purposes. The media company is responsible for the SDS and for passing it to the agency. If the SDS had not been passed correctly, the media company would have defaulted to deemed employer status.

Key Facts