Writing an Outside-IR35-Friendly Working Practices Summary

Writing an outside-IR35-friendly working practices summary

A well-drafted working practices summary is one of the most useful documents a limited-company contractor can hold. It doesn't determine your IR35 status. Only the end client can do that, via a Status Determination Statement (SDS). But a clear, contemporaneous record of how an engagement actually operates is exactly the kind of evidence HMRC expects to see, and it can support your own understanding of a role's position if it's ever questioned.

This guide explains what HMRC's current guidance says such records should cover, why mutuality of obligation and control still matter, and how contractors can approach writing their own summary alongside, not instead of, a proper contract review.

Why HMRC cares about records, not just labels

HMRC's off-payroll working guidance is explicit that organisations must keep detailed, up-to-date records for any engagement where the off-payroll rules are considered. That means recording the facts relied on, the status decision reached, and the reasoning and evidence behind it, not simply filing an SDS and moving on.

HMRC's separate record-keeping guidance goes further, saying records should include the status determination statement itself, the output of any tool used to reach the decision (CEST included, where used), and evidence that the determination was passed to both the worker and any other party in the supply chain. A CEST result on its own is not determinative of status; HMRC's own position is that it is one input, not a verdict, so the surrounding evidence matters just as much as the tool output.

For contractors, this matters because it tells you what a client's compliance file should look like, and by extension, what your own file should mirror if you want a clear picture of how a role has actually been run day to day.

What "working practices" actually means

"Working practices" is the term HMRC and tribunals use for how an engagement operates in reality, as distinct from what the contract says on paper. The two should align, but in practice they sometimes drift apart. A written summary of working practices typically covers:

• Substitution: whether the worker has a genuine, unfettered right to send a substitute, and whether that right has ever been exercised or seriously discussed.
• Control: how much say the client has over what, how, when and where the work is done, and how that control is exercised in practice.
• Financial risk: whether the contractor bears any risk of loss (for example, correcting defective work at their own cost) or invests in their own equipment.
• Integration: whether the contractor is treated as part of the client's organisation (line management, appraisals, staff benefits) or kept separate.
• Provision of equipment: who supplies the tools, software and workspace needed to do the job.

Recording specific, dated examples for each of these, rather than generic statements, is what turns a summary into evidence rather than opinion.

Mutuality of obligation still belongs in the analysis

There has been some debate among contractors about whether mutuality of obligation ("MOO") still matters after the Supreme Court's decision in PGMOL. It does. HMRC's Employment Status Manual confirms mutuality of obligation remains a factor in determining employment status, and cites the Supreme Court's characterisation of mutuality at the first stage as a pre-condition to any contract of employment. The manual also notes that the nature and extent of mutuality can feed into the wider evaluative exercise once that pre-condition is met.

The PGMOL press summary itself found that the minimum requirements of mutuality of obligation and control needed for a contract of employment were satisfied in relation to the individual contracts under consideration. The takeaway for a working practices summary is not "there is no mutuality", but that substitution and control are usually the sharper, more evidential factors to document in detail, alongside a fair account of what obligations, if any, exist between assignments.

How to structure a summary

A practical working practices document should be:

1. Contemporaneous - written or updated at the time, not reconstructed months later from memory.
2. Specific - naming real examples (dates, emails, instances of declined instructions or exercised discretion) rather than general assertions.
3. Cross-referenced - linked to the written contract terms so any gaps between paper and practice are visible, not hidden.
4. Retained - kept alongside the SDS, any CEST output, and correspondence about the determination, mirroring HMRC's own record-keeping expectations under GfC4.

Some listings on outside IR35 job boards describe a role as the client states outside IR35, based on the client's own SDS. That description reflects the client's determination, not a status verified by the platform, and a working practices summary is one of the tools that helps a contractor assess whether the day-to-day reality matches what the paperwork says. For a fuller picture of how engagements are being advertised, you can browse outside-IR35 contracts or check current day-rate benchmarks for comparable roles.

Getting a proper review

Writing your own summary is a useful discipline, but it is not a substitute for a professional contract review. A specialist IR35 reviewer or contractor accountant can assess the written terms against your working practices summary and flag inconsistencies before they become a problem. On broader supply-chain and record-keeping obligations, GOV.UK's off-payroll working collection brings together HMRC's current published guidance, and questions about employment rights and status enforcement sit with the Fair Work Agency, not with a job board or umbrella provider.

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.