Specialist Contractor Accountants: IR35, Limited Company & Tax Planning

IT Contractors

IT contractors represent one of the most IR35-active groups in the UK contracting market. Developers, architects, analysts, project managers, QA engineers, and technology consultants working through a limited company (PSC) face a specific set of financial decisions from structuring their salary and dividend split correctly, to reviewing every new contract for IR35 status, to understanding how the April 2025 small company threshold changes affect who determines their IR35 position from April 2026 onwards.

As specialist accountants for IT contractors, we provide IR35 contract reviews for every new or renewed engagement, advise on outside IR35 working practices and the correct documentation to support them, manage your limited company accounts and payroll, and ensure your personal Self-assessment is correctly prepared each year. We also advise on the changing landscape; as more clients are reclassified as small companies under the revised thresholds, IT contractors need to understand when responsibility for IR35 determination returns to their own PSC.

Engineering Contractors

Engineering contractors; civil, structural, mechanical, electrical, process, and environmental often work on large infrastructure projects for clients that are clearly medium or large under the off-payroll rules. This means the client issues the Status Determination Statement and determines IR35 status. But not all engineering engagements follow this pattern. Project-based contracts with specific deliverables, genuine substitution clauses, and defined output rather than time and attendance point strongly towards outside IR35 and a specialist engineering contractor accountant who understands these distinctions can make a significant difference to how each engagement is assessed and documented.

We advise engineering contractors on IR35 status for each contract, limited company tax efficiency, VAT registration and quarterly returns, the correct treatment of travel and subsistence expenses across multiple sites, and Self-assessment filings that capture every allowable professional cost.

Construction Contractors

Construction contracting brings a specific set of financial obligations that sit outside the standard limited company accounting framework. The Construction Industry Scheme (CIS) applies to most construction sub-contractors; requiring the contractor to verify their subcontractors with HMRC, make the correct CIS deductions, and submit monthly CIS returns. For contractors working under CIS as subcontractors themselves, the deductions withheld at source need to be correctly offset against their tax liability at year end.

Beyond CIS, construction contractors managing multiple sub-contracts simultaneously need clear, timely financial records to track profitability by project, manage cashflow across payment schedules, and maintain the VAT compliance that reverse charge VAT for construction services demands. We provide specialist accountants for construction contractors who understand CIS, reverse charge VAT, and the specific financial structure of construction contracting.

Self-Employed Contractors & Sole Traders

Not every contractor operates through a limited company. Many self-employed professionals across consulting, design, writing, finance, and project management work as sole traders and submit a Self-assessment return each year. A self-employed contractor accountant who understands your income structure, your allowable expenses, your Making Tax Digital obligations from April 2026, and the payment on account system will save you money and eliminate HMRC anxiety.

We advise self-employed contractors on the correct recording of income across multiple clients, the full range of allowable business expenses, quarterly MTD submissions from April 2026, and whether transitioning to a limited company structure would be more tax-efficient given your income level and plans.

IR35 Status Applies Contract by Contract: Not Across Your Whole Practice

A critical point that many contractors and many non-specialist accountants misunderstand is that IR35 status is determined on a contract-by-contract basis. You can be outside IR35 for one engagement and inside IR35 for another running at the same time. Each contract must be assessed individually against the three primary tests: substitution, control, and mutuality of obligation. The determination for one contract does not carry over to another, even where the work is similar.

This matters enormously for your tax planning. If you are running two contracts simultaneously: one outside IR35 and one inside; the tax treatment of income from each is fundamentally different, and your limited company accounts must reflect this correctly. We review every contract individually, advise on the status of each engagement, and ensure your accounts accurately reflect the correct treatment of income from each.

Overlapping Contracts and VAT Timing

When you invoice multiple clients in the same VAT period, the timing of payments, the VAT treatment of each supply, and the correct reconciliation of input and output VAT all need to be managed carefully. For contractors approaching the £90,000 VAT registration threshold across their combined contract income, timing of registration matters. For those already registered, the correct and timely submission of quarterly VAT returns across multiple revenue streams prevents penalties and HMRC attention.

Multiple Contracts and the Making Tax Digital Transition

From April 2026, self-employed contractors with gross income above £50,000 must maintain digital records and submit quarterly updates to HMRC under Making Tax Digital for Income Tax. For contractors working across multiple clients and multiple contract types, the record-keeping requirements increase in complexity. We set up your digital records correctly from the outset; ensuring each income stream is captured, categorised, and reported as MTD requires, without adding material administrative burden to your contracting schedule.

Contract Gaps, Bench Periods, and Cashflow

Contractors between contracts face a different cashflow dynamic from employees; there is no sick pay, no notice pay, and no statutory protections that maintain income during a gap. Proper financial planning during active contracts including sensible retained profit strategies within your limited company, correct payment on account management, and awareness of VAT payment dates makes bench periods manageable rather than stressful. We advise on this as part of every ongoing contractor engagement.

IR35 and Overseas Clients: A Critical Exemption

This is one of the most important and most frequently misunderstood aspects of IR35 for contractors with international clients. The off-payroll working rules that require medium and large private sector clients to determine IR35 status and issue a Status Determination Statement do not apply where the engager is based wholly overseas. If your client is an overseas business with no UK presence, the responsibility for IR35 determination remains with your own PSC under Chapter 8 of ITEPA 2003 regardless of the client's size.

This does not mean you are automatically outside IR35; the three status tests still apply. But it does mean that you, rather than your client, are responsible for making the determination and demonstrating reasonable care in doing so. An incorrect determination exposes your PSC to backdated tax, NIC, interest, and penalties. We review contracts with overseas clients carefully, assess IR35 status under Chapter 8, and document the reasonable care your PSC has applied to the determination.

VAT on Services to Overseas Clients

The VAT treatment of services supplied to overseas clients depends on where the client is established and whether they are a business or a consumer. For business-to-business supplies of services to clients established outside the UK, the general rule is that the supply is outside the scope of UK VAT meaning you do not charge VAT, but you may still need to report the supply on your VAT return as a reverse charge or under the UK's general B2B place of supply rules. The rules differ depending on the country of the client and the nature of the services provided.

Getting this wrong either by charging VAT where none is due or by failing to account for VAT correctly on cross-border supplies; creates compliance risk and can affect your relationship with international clients. We advise on the correct VAT treatment for every overseas client engagement and ensure your VAT returns reflect cross-border supplies accurately.

Invoicing in Foreign Currency

Contractors invoicing overseas clients typically do so in the client's currency: USD, EUR, AED, or others. All income must be reported to HMRC in pounds sterling, which means every invoice and every payment must be converted at the appropriate rate. HMRC accepts the use of a published exchange rate (such as the HMRC approved monthly rates or a commercial bank's closing rate on the payment date). We manage currency conversion correctly across your records, ensure your VAT return reflects the sterling equivalent of foreign currency invoices, and document the conversion methodology used protecting your position in the event of HMRC scrutiny.

Working in the UAE or Other Jurisdictions

Some UK contractors take on engagements that require them to be physically present in another country for an extended period. This creates residence and tax treaty questions: how many days can you spend in a jurisdiction before becoming tax resident there? Does the UK have a double tax treaty with the country concerned? Does your income from that engagement remain taxable in the UK, or does an exemption apply under the treaty? And what are your UK obligations during the period abroad?

As a practice serving both UK and UAE clients, we have specific expertise in advising contractors who work between the UK and UAE, manage income from UAE-based engagements, or are considering a period of residency in the UAE. We also advise contractors working in other jurisdictions on the statutory residence test, split-year treatment, and the interaction between their UK and overseas tax positions.

What IR35 Is and Why It Matters

IR35 is HMRC's off-payroll working legislation, designed to prevent contractors from using a limited company structure to take home significantly more money than a direct employee doing equivalent work. If your working arrangement would, in substance, make you an employee of the client if you were engaged directly rather than genuinely operating as an independent business, HMRC treats the income as employment income, subject to PAYE and National Insurance. Being determined as inside IR35 means your fee payer must deduct income tax and NICs before paying you, reducing your take-home by the equivalent of employment taxes.

The Three Status Tests

HMRC assesses IR35 status through three primary tests, applied to the substance of the working arrangement rather than the wording of the contract alone.

Substitution: can you send a genuine substitute to perform the work in your place, without the client's consent being required for the specific individual?

Control: does the client control how the work is done, or only what outcome is delivered?

Mutuality of obligation: is the client obliged to offer work, and are you obliged to accept it?

Strong genuine substitution, limited control, and clear absence of mutuality all point towards outside IR35. The presence of the opposite in each case points inside.

What Changed in April 2025 and April 2026

April 2025 brought a significant change to the definition of a small company: the threshold below which private sector clients are exempt from the off-payroll rules and PSCs determine their own IR35 status. The annual turnover threshold rose from £10.2 million to £15 million, and the balance sheet threshold from £5.1 million to £7.5 million (with the employee count remaining at fewer than 50). This reclassified approximately 14,000 UK businesses from medium to small.

From April 2026, the practical effect of this reclassification applies to engagements with newly small clients; meaning that if your client has crossed the threshold into small company status, responsibility for the IR35 determination returns to your PSC from that point. You are now responsible for assessing your own status for that engagement and must be able to demonstrate reasonable care. Contractors who were previously relying on their client to issue a Status Determination Statement and absorb the compliance risk now need to review each affected engagement and manage the determination themselves.

Also from April 2025, a PAYE set-off mechanism was introduced; allowing tax already paid through PAYE within the engagement to be taken into account if HMRC later assesses a liability at the PSC level. This reduces the risk of double taxation for contractors who have already paid tax through an inside IR35 arrangement.

Our IR35 Service

We provide written contract reviews for every new or renewed engagement, assessing IR35 status against the three primary tests and the current client size rules. We advise on working practice documentation: the records you should maintain throughout the engagement to support the outside IR35 position. We respond to Status Determination Statements you disagree with and advise on the formal 45-day challenge process. And we provide ongoing monitoring as your client portfolio changes and as the IR35 landscape continues to evolve.

IR35 Accountant & Contract Review Service

We review every new or renewed contract against the three IR35 status tests; substitution, control, and mutuality of obligation and provide a written assessment of your IR35 position for that engagement. We identify clauses in your contract that could weaken an outside IR35 position and advise on amendments. We also advise on working practices and the documentation you should maintain throughout each engagement to support the determination.

Following the April 2025 client reclassification changes, we review the size status of each of your clients and advise on whether IR35 determination responsibility has shifted to your PSC for any of your active engagements.

Best for: All limited company contractors - IT, engineering, construction, and other sectors; before signing any new contract or renewing an existing one.

Contractor Limited Company Accountant Service

We provide a complete limited company accounting service for contractors operating through a PSC including book-keeping, payroll, director salary and dividend planning, quarterly VAT returns, annual statutory accounts, Corporation Tax filing, and Confirmation Statement submission to Companies House. We also prepare your personal Self-assessment return as a director, bringing your employment income, dividends, and any other personal income together into a single correctly prepared return.

We advise on the optimal salary and dividend split for your income level, taking into account the current National Insurance thresholds, the employer NIC increase to 15 per cent from April 2025, the Employment Allowance, and the most tax-efficient approach to extracting profit from your limited company.

Best for: All contractors operating through a limited company (PSC), from new company formations through to established multi-year contracting businesses.

Contractor Self-Assessment Accountant

Whether you contract as a sole trader, operate through a limited company and need to report director income and dividends, or have additional income from investments, rental property, or overseas sources alongside your contracting income; we prepare your annual Self-assessment return with a full review of every income source and every allowable expense before submission.

For contractors approaching or subject to Making Tax Digital for Income Tax from April 2026, we set up your quarterly digital submission process, configure the right software, and manage your MTD obligations as part of the ongoing service.

Best for: Sole trader contractors, limited company directors with personal tax obligations, and contractors with additional income sources beyond their primary contracting income.

Contractor VAT Registration & Quarterly Returns

We advise on VAT registration timing, scheme selection (standard, flat rate, or cash accounting), and the correct VAT treatment for your specific contracting income including cross-border services for overseas clients, reverse charge VAT for construction services under CIS, and the treatment of mixed contracts where different elements carry different VAT rates.

We prepare and submit your quarterly VAT returns accurately and on time, manage any VAT errors or corrections, and advise on VAT reclaim on business expenses including equipment, software, and professional subscriptions.

Best for: All VAT-registered contractors and those approaching the £90,000 VAT registration threshold across their contract income.

CIS Compliance for Construction Contractors

Construction contractors operating under the Construction Industry Scheme face specific obligations; monthly CIS returns, verification of subcontractors, correct deduction rates (20 per cent standard or 30 per cent unverified), and the offsetting of CIS deductions received against the company's PAYE and Corporation Tax liability. For construction contractors working as subcontractors under CIS, we ensure that deductions withheld at source are correctly claimed back and that your monthly returns are filed on time to avoid penalties.

We also advise on the reverse charge VAT rules for construction services, which apply to most VAT-registered construction supplies between VAT-registered businesses in the construction sector and require careful application to avoid incorrect VAT accounting.

Best for: Construction contractors and sub-contractors operating under CIS whether as the main contractor deducting from subcontractors or as a subcontractor having deductions made.

Contractor Tax Adviser - Year-Round Tax Planning

Effective tax planning for a contractor goes beyond choosing the right salary and dividend split. We review your complete financial position - retained profits in your limited company, pension contributions through the company, investment income, property, and any overseas income - and develop a structured approach to managing your overall tax burden across the year.

This includes advice on employer pension contributions from your limited company (which reduce Corporation Tax and avoid National Insurance), the correct treatment of home office and equipment expenses, business mileage, professional development costs, and the timing of dividend payments to make best use of annual allowances.

Best for: Established contractors with growing retained profits in their limited company, those approaching higher rate tax thresholds, and contractors with diverse income sources who want a structured, year-round planning approach.

Contractor Payroll & Director Remuneration

We manage your limited company payroll; processing your director salary each month, submitting Real Time Information (RTI) returns to HMRC, managing auto-enrolment pension obligations where applicable, and producing payslips and year-end P60s. We advise on the optimal director salary level each April as National Insurance thresholds and rates change, ensuring your remuneration structure remains as tax-efficient as possible.

Best for: All limited company contractor directors requiring a managed payroll service with ongoing advice on director remuneration levels.

Contractor Book-keeping - Year-Round Record Keeping

Accurate, up-to-date records are the foundation of every other service we provide. Our book-keeping for contractors service covers invoice management, bank reconciliation, expense categorisation, and the preparation of records that make your VAT returns, payroll, Self-assessment, and Making Tax Digital submissions straightforward throughout the year. We work across Xero, QuickBooks, FreeAgent, and Sage, and we recommend the right platform for your income level and complexity.

Best for: Contractors who want their financial records maintained accurately throughout the year rather than compiled under pressure at year end.