How to Choose a Contractor Accountant in the UK

Why the choice of accountant matters more for contractors than for most businesses

A sole trader running a local shop and a limited-company contractor both need accounts filed and tax returns submitted. The technical overlap ends there. A contractor operating through a Personal Service Company (PSC) sits inside a web of legislation that a general practice accountant may never have encountered: IR35 and the off-payroll working rules (Chapters 8 and 10 of ITEPA 2003), the profit extraction calculus that changed again in April 2026, employer pension contributions as the primary tax-efficient lever, and the Managed Service Company provisions in Chapter 9, which carry personal debt transfer and are currently at the centre of live litigation. An accountant who does not know these areas cold is not a cheaper version of a contractor specialist. They are a different product entirely.

This guide sets out what a contractor accountant must cover, how to test whether a candidate firm actually covers it, and one legal risk that most contractors have not heard of until it is too late.

The IR35 literacy test: Chapter 8 versus Chapter 10

The single most important thing a contractor accountant needs to understand is that "IR35" covers two separate regimes operating under different mechanics. What IR35 is and how it works is covered in detail elsewhere; what matters here is that a prospective accountant can distinguish between them without a prompt.

Chapter 8 (the original intermediaries legislation) applies where the end client is a small company (or based wholly overseas with no UK connection). The PSC is responsible for assessing its own status and, if inside IR35, calculating and operating a deemed employment payment at year-end. The 5% flat administrative expenses allowance applies under Chapter 8. The contractor's accountant is the person doing the heavy lifting on this assessment.

Chapter 10 (the off-payroll working rules) applies where the end client is medium or large. Here the client issues a Status Determination Statement (SDS), the fee-payer (usually the agency closest to the PSC) operates PAYE and employee NIC before paying the PSC, and the fee-payer also bears employer NIC at 15% on earnings above the secondary threshold of £5,000 (2026/27). There is no 5% allowance under Chapter 10. The mechanics, the liabilities and the planning options are materially different from Chapter 8.

The dividing line is client size. "Small" for this purpose means meeting two or more of the three Companies Act 2006 s.382 conditions: turnover not more than £15m, balance sheet total not more than £7.5m, not more than 50 employees (thresholds raised for financial years beginning on or after 6 April 2025). Because of the relevant-financial-year lag and the two-consecutive-years rule in s.382(2) and ITEPA s.60A, most clients that were medium before 2025 will still be medium for 2026/27 purposes; the earliest they could fall out of Chapter 10 scope is 6 April 2027, and for many year-ends it is 6 April 2028. A contractor's accountant should be able to explain this without prompting.

Ask a prospective accountant: who operates PAYE under a Chapter 10 inside determination, and what is the difference in the expenses treatment? If they cannot answer, move on.

Status support: contract reviews, CEST and working practices

An accountant cannot determine a contractor's IR35 status by themselves, and it would be a red flag if they claimed they could. Status turns on the facts of the engagement weighed against the three core tests established in Ready Mixed Concrete (South East) Ltd v Minister of Pensions [1968] 2 QB 497: personal service (and the right of substitution), control, and mutuality of obligation, with the whole picture then assessed in the round. The Supreme Court in PGMOL v HMRC [2024] UKSC 29 confirmed that mutuality of obligation and control are necessary conditions but not sufficient: a tribunal must still stand back and ask whether the overall picture is one of employment. Protecting an outside-IR35 position requires more than good contract wording.

What a contractor specialist can and should do is help model and document the engagement against those tests, flag risk areas, and support a challenge when a determination looks wrong.

CEST: a useful screen, not a guarantee

HMRC's Check Employment Status for Tax tool (CEST, updated 30 April 2025) tests substitution, control and financial risk, and now includes a dedicated mutuality of obligation question and an upfront contract gate. HMRC says it will stand behind a CEST result where the inputs are accurate, consistent with the actual working practices, in line with its guidance, and there is no avoidance. That promise matters as an audit-trail document. But it has limits. CEST does not bind a tribunal. Its treatment of mutuality of obligation is narrower than the case law, so it can return "outside" or decline to determine on facts a tribunal would view differently. A result that does not reflect the real working practices is worthless regardless of what the contract says.

A contractor accountant should treat CEST as a first screen paired with a contract review and a working-practices assessment. Neither the contract alone nor CEST alone is sufficient. How an SDS is assessed and challenged runs deeper than a CEST run-through.

The 45-day SDS disagreement process

Under Chapter 10, the client issues the SDS. If the contractor believes the determination is wrong, ITEPA s.61T gives the right to trigger the client-led disagreement process: the client must consider the representations and respond within 45 days, either confirming the original determination with reasons or issuing a revised one. A blanket determination applied to a whole category of contractors without individual assessment is likely a failure of the reasonable-care requirement in ITEPA s.61NA, which can invalidate the SDS and shift the liability to the client itself. A contractor accountant should be able to help draft a representation and advise on what working-practice evidence supports it.

Extraction planning: the 2026/27 numbers have changed

The core extraction choice for a PSC director is between salary (deductible against corporation tax, subject to PAYE and NIC) and dividends (paid from post-tax profit, taxed at dividend rates, no NIC). Finance Act 2026 s.4 changed the arithmetic from 6 April 2026.

Dividend rates for 2026/27

From 6 April 2026, dividend rates are: ordinary 10.75%, upper 35.75%, additional 39.35% (unchanged). The dividend allowance is £500. This means a basic-rate PSC director pays 10.75% on dividends above £500 within the basic-rate band, against 8.75% in 2025/26. The incorporation advantage over a comparable employment has narrowed, and the case for maximising pension contributions has strengthened relative to dividends.

Dividends are taxed after non-savings and savings income, in their own bands. A director approaching the £50,270 higher-rate threshold (frozen to April 2031) or the £100,000 personal allowance taper needs modelling that reflects exactly where dividends land in the order of taxation. Fiscal drag is now a live planning theme: the freeze to 2031 means more contractors will cross band boundaries each year without a pay rise in real terms.

Salary level: the Employment Allowance fork

There is no single optimal salary for a PSC director in 2026/27. The right level turns on Employment Allowance eligibility. A company whose sole employee is a single director cannot claim the Employment Allowance (worth £10,500 for 2026/27), so it bears employer NIC at 15% on salary above the secondary threshold of £5,000. For that structure, salary is typically set between £5,000 and the lower earnings limit of £6,708, accepting a small employer NIC charge on the slice above £5,000 as the price of securing a qualifying NI year. Some single-director companies choose exactly £6,708 for clarity on the NI year; the right figure depends on the numbers modelled. A company that can claim the Employment Allowance (for example because a genuinely employed spouse or other staff member is also on the payroll) can generally justify salary up to the personal allowance of £12,570, where the Employment Allowance absorbs the employer NIC and the corporation tax saving on the additional salary outweighs the employee NIC cost.

An accountant who gives you a single salary figure without asking about Employment Allowance eligibility, other income sources, and your corporation tax marginal rate is not doing the job properly. See PSC limited company tax for the full corporation tax context.

Corporation tax: the base from which everything else flows

For 2026/27 (Financial Year 2026), the corporation tax rates are unchanged from FY2025: small profits rate 19% on profits up to £50,000, main rate 25% on profits above £250,000, with marginal relief between them producing an effective marginal rate of around 26.5% on profits in that band. Finance Act 2026 made no change to corporation tax rates. The £50,000 and £250,000 thresholds are divided by the number of associated companies, which matters if the contractor's spouse also runs a PSC under common control. An accountant who does not ask about associated companies when modelling the extraction is missing a structural question.

The pension lever: the biggest efficiency most contractors underuse

An employer pension contribution from the PSC is consistently the most tax-efficient extraction route available to a PSC director. It is deductible against corporation tax on a paid basis (Finance Act 2004 s.196), carries no employer or employee NIC, and is not taxed on the director as income when paid in, subject to the annual allowance. No other extraction route matches this combination.

For 2026/27, the annual allowance is £60,000, measured across all contributions (employer and personal combined). It tapers where threshold income exceeds £200,000 and adjusted income exceeds £260,000, reducing by £1 for every £2 of adjusted income above £260,000, down to a minimum of £10,000. Unused annual allowance can be carried forward from the previous three tax years (current year used first), which allows a large one-off employer contribution in a high-profit year or before a company sale. The money purchase annual allowance (MPAA) is £10,000 and is triggered if the director has flexibly accessed a defined-contribution pension; after that, carry-forward is lost for DC contributions. A contractor who has already drawn flexibly from a pension needs their accountant to flag the MPAA before making any further contributions.

Critically, an employer (company) contribution is not limited by the director's salary, unlike a personal contribution which is capped at 100% of relevant UK earnings. Since a low-salary/high-dividend director has limited personal contribution headroom, the employer route is almost always the right structure. A contractor accountant should be modelling pension contributions as the primary question, not an afterthought. See contractor employer pension contributions for more on the mechanics, including carry-forward planning.

MTD for Income Tax: what it means (and does not mean) for PSC contractors

Making Tax Digital for Income Tax has a phased rollout based on qualifying income (gross self-employment and property income, not salary or dividends): £50,000 from 6 April 2026, £30,000 from 6 April 2027, £20,000 from 6 April 2028. It applies to sole traders and landlords in Self Assessment. It does not apply to limited-company directors in respect of their salary and dividends, which are not qualifying income. The company itself files corporation tax, not Self Assessment, and is entirely outside MTD for IT.

For a typical PSC contractor whose only personal income is a director's salary and dividends from their own company, MTD for IT is irrelevant. If the contractor also has sole-trader income or property rental income above the relevant threshold, that strand is in scope and requires digital record-keeping and quarterly updates to HMRC from the relevant date. A contractor accountant should identify whether any of their clients are caught and set up the right software workflow in advance, not in a rush when the deadline arrives. The VAT and MTD compliance picture sits alongside this for VAT-registered contractors.

The Managed Service Company risk: the boundary that determines which accountant you should choose

The Managed Service Company legislation (ITEPA 2003 Chapter 9, in force from 6 April 2007) is the risk most contractors have not encountered until they are deep inside it. It is separate from IR35 entirely and operates differently: there is no status test to argue. If HMRC determines that a company is an MSC, all payments to the worker are treated as employment income subject to PAYE and NIC. Unpaid PAYE can be transferred as a personal debt to the worker, the company's directors and the MSC provider under ITEPA s.688A and the MSC Regulations 2007 (SI 2007/2053).

A company is broadly an MSC where its business wholly or mainly involves providing an individual's services, payments to the worker represent most of the company's income, those payments exceed what PAYE would give, and an "MSC provider" is involved in the company. The involvement test asks whether the provider promotes or facilitates the use of companies to provide individuals' services and takes a role in running them.

The accountancy carve-out and the advice-versus-product boundary

ITEPA s.61B(3) provides that a person is not an MSC provider merely by providing legal or accountancy services in a professional capacity. This is the carve-out that genuine independent contractor accountants rely on. The danger zone is where the "accountant" goes beyond advice: influencing or controlling the company's finances, determining how the worker is paid, or providing a packaged, standardised "your-company-run-for-you" product where the client has limited real decision-making control and could not freely move their company elsewhere. A genuine independent accountant who advises clients, where the clients make their own decisions and could switch firms without restructuring, is on the safe side of the line.

The Court of Appeal confirmed the two-stage MSC-provider test in Christianuyi Ltd v HMRC [2019] EWCA Civ 474. HMRC has since pursued the accountancy firms Churchill Knight and Boox, arguing their packaged products crossed the s.61B(3) line. Those test cases are listed for First-tier Tribunal hearings in June 2026 and November 2026 and have not yet produced a final binding decision; appeals are likely beyond the FTT whatever the outcome. The correct posture is not to wait and see. Because personal debt transfer is one of the consequences of an MSC finding, the decision about which accountant to use is a risk-management decision with legal weight. Choose an accountant whose model is clearly on the advice side of the boundary. The advice-not-product distinction is the decisive lens here, not a claim about any named firm.

Questions to ask a prospective accountant on this point: do they operate a standardised packaged structure for all clients, or do they advise each client individually? Does the client have genuine control over their own company's decisions, or does the accountant or a related party make those calls? Can the client take their company to a different accountant without the structure unravelling? A confident answer to all three in the direction of genuine independent advice is what you want.

The off-payroll debt chain and what it means for your accountant relationship

Where a fee-payer fails to operate PAYE correctly under Chapter 10, or a client fails to take reasonable care when issuing an SDS, HMRC can pursue parties up the supply chain. A client that issues a blanket inside-IR35 determination across a whole category of contractors without assessing each engagement individually has very likely failed the reasonable-care requirement in ITEPA s.61NA, invalidating the SDS and moving the liability to the client. The off-payroll debt-transfer provisions give HMRC tools to recover from the client directly.

From 6 April 2024, a statutory set-off (offset) reduces the deemed employer's PAYE liability by an estimate of taxes already paid by the worker and PSC on the same income (corporation tax on PSC profits, income tax and employee NIC on salary, income tax on dividends from relevant profits). The offset operates on a trigger event, typically a Regulation 80 determination. It reduces but does not eliminate the exposure, and it does not cover employer NIC, which was never paid. A contractor accountant should be able to explain this clearly because it affects how much a retrospective HMRC investigation actually costs both sides.

The off-payroll working rules for the private sector cover the full SDS chain, debt transfer and fee-payer mechanics, and a specialist accountant should be able to walk you through each link of that chain.

VAT registration and the Flat Rate Scheme

Most contractor services are standard-rated at 20%. Compulsory VAT registration applies once VAT-taxable turnover exceeds £90,000 in any rolling 12 months (deregistration threshold £88,000; both frozen since 1 April 2024). Many contractors register voluntarily below the threshold to reclaim input VAT and because their clients, typically VAT-registered businesses, can recover any VAT charged.

The Flat Rate Scheme (FRS) allows a business with expected taxable turnover of £150,000 or less (ex-VAT) to pay a fixed percentage of VAT-inclusive turnover instead of tracking input VAT. For a labour-only contractor, however, the limited-cost trader rate of 16.5% applies where the business spends less than 2% of turnover, or less than £1,000 per year, on goods. At 16.5% the FRS typically produces a worse outcome than standard VAT accounting for a contractor with minimal goods purchases. A good accountant models the position for each VAT period, rather than assuming the FRS is automatically beneficial because it was sold that way when the contractor first registered.

Umbrella versus PSC: the accountant's role in the decision

For a genuinely inside-IR35 engagement, an umbrella company is often the simpler and more economical structure: no PSC running costs, no corporation tax filings, no double layer of PAYE administration. The umbrella employs the contractor under an overarching contract of employment, operates PAYE and NIC on the assignment income, and pays a salary. Employer NIC at 15%, the Apprenticeship Levy and the umbrella's margin come out of the assignment rate (they are not deducted from gross salary), so the umbrella "day rate" is not equivalent to a PSC day rate for the same contract. A compliant umbrella must provide a Key Information Document showing the rate, deductions and expected take-home before the assignment starts.

From 6 April 2026, Finance Act 2026 s.24 inserted new Chapter 11 (ITEPA ss.61Y to 61Z2), making the recruitment agency that contracts with the end client (or the end client itself where there is no agency) jointly and severally liable with the umbrella for any PAYE and NIC the umbrella fails to remit. The umbrella remains the legal employer; what changed is that HMRC can now pursue the agency or end client for unpaid umbrella PAYE. The practical consequence is that agencies and clients have tightened their preferred-supplier-list controls considerably. An accountant who understands the umbrella versus limited company question can help a contractor assess which structure fits their specific engagement mix, rather than defaulting to one without the analysis.

Keeping a PSC makes most sense where the contractor holds some outside-IR35 work alongside an inside engagement, wants to retain and invest profits in the company, or has pension and structuring goals that reward the company structure. The inside/outside mix of work is the primary decision driver.

What a specialist contractor accountant's service should look like in practice

A specialist contractor accountant should, as a minimum, cover the following areas without being prompted.

At onboarding: confirm the applicable IR35 chapter for each client engagement (and the client-size position where relevant), set up payroll for the director's salary at the right level for the EA position, register for VAT if appropriate and model FRS versus standard, establish a bookkeeping system and document-retention workflow, and confirm whether the contractor has any pension carry-forward available from the prior three years.

During the year: flag any SDS received and advise whether to challenge it, model any changes to the engagement that affect the temporary-workplace rule (24 months / 40% of working time at one site, expectation-based), update the extraction model when rates change, and run the salary/dividend/pension optimisation for the tax year in progress.

At year-end: complete the corporation tax return and annual accounts, prepare the director's Self Assessment incorporating the salary, dividends and any other personal income, review the pension position against the annual allowance and flag carry-forward opportunities, and check the s.455 director's loan account position (the charge is 35.75% on loans outstanding nine months and one day after the period-end where the loan was made on or after 6 April 2026, at the new dividend upper rate).

On the MSC question: be able to explain why their service model sits on the advice side of the ITEPA s.61B(3) line, and why the Churchill Knight and Boox litigation (undecided at the time of writing, with hearings in 2026) matters to that analysis.

Red flags when evaluating contractor accountants

Several signals indicate that a contractor accountant is not the specialist they present themselves as.

• They cannot distinguish Chapter 8 from Chapter 10. This is the foundation. If the distinction requires an explanation from you, they are not a contractor specialist.
• They give you a single "optimal salary" figure without asking about Employment Allowance eligibility. The right salary depends on your specific structure. A generic figure is a sign of template advice, not individual modelling.
• They quote 8.75% or 33.75% dividend rates for 2026/27. Finance Act 2026 raised these to 10.75% and 35.75% from 6 April 2026. Using the old rates will understate your personal tax bill.
• They treat CEST as conclusive. A "CEST says outside" delivered without a working-practices review is incomplete advice. It is a useful tool with documented limits.
• They have never heard of the MSC legislation. ITEPA Chapter 9 with its personal debt-transfer exposure is a real risk for PSC contractors and the accountant should know it exists and be able to explain the s.61B(3) boundary.
• Their service looks like a standardised packaged product rather than individual advice. In the context of the Churchill Knight and Boox litigation, this is not just a service-quality concern; it is a legal risk factor.
• They do not mention pension contributions as the primary tax lever. For most PSC directors, the employer pension contribution is a more efficient extraction route than dividends at 2026/27 rates. An accountant who leads with dividends and mentions pensions as an afterthought is not optimising your position.

Working with your accountant: what you need to provide

The quality of a contractor accountant's advice depends heavily on what the contractor provides. At the start of the engagement, share every contractor agreement (not just the most recent), the details of each client (size, sector, structure of the engagement, how work is actually supervised and delivered), any SDS documents received, existing bookkeeping records, and details of any other income, pensions or investments that affect the personal tax calculation.

During the year, report any changes to the engagement immediately: a contract extension beyond 24 months at the same site triggers the temporary-workplace rule from the point at which that extension is expected, not retrospectively at the 24-month mark. A new client, a change in how work is supervised, or a role that shifts from outside to inside IR35 mid-year all have tax consequences that are much easier to manage prospectively than retrospectively.

The mileage rate changed on 6 April 2026: 55p per mile for the first 10,000 business miles (up from 45p) and 25p thereafter, under the approved mileage allowance payment rates. Keep a contemporaneous mileage log, since HMRC expects records to be maintained at the time, not reconstructed. Ordinary commuting (home to a permanent workplace) does not qualify.

Choosing a specialist: the one question that cuts through the noise

After discussing fees, software and service scope, ask the prospective accountant this: "If HMRC investigates and argues that my company is a Managed Service Company under ITEPA Chapter 9, how does your service model protect you and me from that characterisation?" A genuine contractor specialist will explain the ITEPA s.61B(3) accountancy carve-out, describe how their service model keeps the advice/product boundary clear, and acknowledge the current litigation without overclaiming certainty about its outcome. A generalist will not know what you are asking. A provider whose model is itself at risk under Chapter 9 will give you an answer worth examining very carefully.

The answer to that question tells you more about the quality and legality of the accountant's service than any number of testimonials or website rankings.

Getting started with the right specialist

Choosing a contractor accountant is a risk-management decision as much as an efficiency one. The right firm understands IR35 at the level of individual engagement mechanics, keeps extraction planning current with the rates in force, treats pension contributions as the primary lever, explains the MSC boundary with clarity, and can tell you exactly where the advice/product distinction sits in their own service model.

If you operate through a PSC or are considering setting one up, our team works exclusively with UK limited-company contractors and covers IR35 status support, extraction planning, pension strategy and full compliance. Check your IR35 position or get in touch to discuss your specific situation.