IR35 AccountantsIR35 Contract Reviews
Clause-by-clause review of your contract and working practices against the status tests HMRC and the tribunals actually apply, with a written outside or inside opinion you can rely on.
Three-stage test from Ready Mixed Concrete (1968) · PGMOL (Supreme Court, 2024) on mutuality · Written opinion you can show HMRC
IR35 Contract Reviews: what you need to know
Most contractors come to a contract review at one of three moments: a new contract is on the table, a renewal is due, or their end client has just dropped below the small-company thresholds that rose to £15m turnover and £7.5m balance sheet on 6 April 2026 and handed the status decision back to them. Roughly 14,000 engagers became small at that date, so a determination that used to be someone else's problem is now sitting on the contractor's desk.
A proper review works clause by clause through the three stages the courts have applied since Ready Mixed Concrete in 1968: personal service and any right of substitution, mutuality of obligation, and control over how the work is done. After the Supreme Court's 2024 decision in PGMOL the mutuality stage is read narrowly, which pushes more weight onto control and the in-business factors the Court of Appeal examined in Atholl House. The reviewer then tests whether your day-to-day working practices actually match the paper.
A contract that reads outside but is worked inside fails at tribunal, and the gap between the two is where most lost cases are decided. The stakes are not abstract: HMRC can assess four years back for an innocent error and six where carelessness is shown, while a documented professional review is the standard evidence of reasonable care that holds penalties at 0%. We deliver a written opinion, flag the clauses that need renegotiating, and tell you plainly when an engagement cannot honestly be called outside.
What you get
Tested against real case law
Our reviews run the full tribunal framework, including the post-PGMOL reading of mutuality and the Atholl House in-business factors, not a checkbox questionnaire.
Working practices, not just paper
The written terms are half the picture. We interview you on substitution, supervision and integration so the opinion reflects how the engagement actually runs.
Reasonable care on the record
A dated professional opinion is the cleanest evidence that you took reasonable care, which is what keeps HMRC's assessment window at four years and penalties at nil.
Renegotiation ammunition
You get the specific clauses to push back on, with suggested wording, so the conversation with your agency or client is about drafting rather than opinion.
What's covered under ir35 contract reviews
We handle the full range of work that sits within ir35 contract reviews, including:
Outside IR35 contract review
A clause-by-clause written opinion on whether a specific engagement sits outside the intermediaries legislation, with the reasoning a tribunal would recognise.
Working practices assessment
A structured questionnaire and interview that tests how the role is actually performed, because tribunals weigh reality over drafting when the two diverge.
CEST second opinion
A specialist check of a CEST output, useful where the tool returned no determination or where the answers given do not survive scrutiny against the case law.
Contract renegotiation support
Marked-up clauses and suggested substitution, control and termination wording you can take back to the agency or client before signing.
Pre-renewal status reassessment
A fresh look at a long-running engagement before extension, since length of service, integration and changed duties can erode a position that was sound at the start.
Confirmation of arrangements letters
A statement of working practices signed by the end client, one of the strongest single pieces of contemporaneous evidence an outside position can hold.
Who this is for
We regularly take on engagements like these:
- An IT contractor whose end client fell under the new £15m and £7.5m small-company thresholds in April 2026 and must now determine status for the first time in five years.
- An interim finance director signing a twelve-month engagement who wants the substitution and control clauses tested before the contract is executed.
- An engineering consultant whose CEST run returned no determination and who needs a reasoned written opinion to fill the gap.
- A contractor whose agency reissued a renewal on materially different terms and who suspects the new wording quietly moved the engagement inside.
- A locum professional planning a portfolio of shorter engagements who wants a working-practices framework agreed up front rather than reviewing each contract from cold.
How an engagement works
Describe the engagement
Tell us about the contract, the client and what is worrying you. Two minutes of detail is enough to quote accurately.
Fixed written quote in 48 hours
We quote a fixed fee for the review before anything starts. No hourly meters, no surprises on the invoice.
Send the contract
Once you accept, you send the contract and answer the working-practices questions that test how the role actually runs.
Receive the written opinion
You get a written opinion with the reasoning a tribunal would recognise, the clauses to renegotiate, and a plain verdict either way.
Read before you decide
The guides library covers the rules behind this service in depth.