Claiming Car Expenses in a Limited Company or as Self-Employed: What HMRC Allows (And What It Will Challenge)

Car expenses are one of the most misunderstood and incorrectly claimed business expenses in the UK. Many limited company directors and self-employed individuals assume that because they use their car for work, they can put the car “through the company” and claim all fuel, insurance, repairs, and finance. This is not how UK tax law works — and HM Revenue & Customs is actively challenging incorrect car expense claims during compliance checks and enquiries.

This article explains the difference between company cars and personal cars, common mistakes that trigger HMRC investigations, what expenses are legitimately allowable, and the tax consequences of getting it wrong.

Why HMRC Closely Scrutinises Car Expense Claims

Vehicle costs are attractive deductions — and therefore high risk from HMRC’s perspective. HMRC regularly challenges:

• Directors claiming all car costs via the company
• High fuel and repair costs with no mileage records
• Cars used mainly for personal travel
• Confusion between company cars vs personal cars
• Claims inconsistent with business size or turnover

Incorrect claims can lead to disallowed expenses, backdated Corporation Tax or Income Tax, Benefit in Kind (BIK) charges, and significant penalties.

Key Rule: A Car Cannot Be “Partly Business” for Tax Ownership Purposes

This is where many people go wrong. A car is either a company car or a personally owned car. There is no hybrid option for ownership.

Limited Company Directors: How Car Expenses Really Work

Option 1: Company Car (High Tax Cost for Most Directors)

A car is a company car if the company buys or leases it, pays running costs, and the car is available for any personal use.

Tax Consequences:

• Benefit in Kind (BIK) tax on the director
• Class 1A National Insurance for the company
• Additional fuel benefit if fuel is provided

Warning: For petrol and diesel cars, BIK can be extremely expensive. Company cars are usually only tax-efficient for fully electric or ultra-low emission vehicles.

Option 2: Personal Car Used for Business (Most Common & Safest)

If the director personally owns the car, the company must NOT pay car expenses directly. Instead, the company can reimburse business mileage only.

HMRC Approved Mileage Rates:

• 45p per mile for first 10,000 miles
• 25p per mile thereafter

Benefits: Covers fuel, insurance, servicing, depreciation; No Benefit in Kind; Simple and low risk.

Restriction: The company cannot separately pay for fuel, insurance, repairs, or finance.

Common Director Mistakes That HMRC Challenges

We frequently see directors incorrectly claiming car finance or lease payments, putting insurance and repairs through the company, claiming 100% fuel costs, or claiming commuting as business mileage. HMRC treats this as careless or deliberate behaviour depending on scale.

Self-Employed Individuals: Different Rules, Same Risks

For sole traders and partnerships, HMRC allows two methods, but you must choose one.

Method 1: Simplified Mileage Method

• Claim mileage using HMRC rates
• No separate vehicle costs claimed
• No capital allowances
• Verdict: Lowest risk method.

Method 2: Actual Cost Method (Strict Records Required)

You may claim the business proportion of fuel, insurance, repairs, servicing, road tax, and capital allowances.

Requirements: Accurate mileage logs, business vs personal use calculation, and consistency year-to-year. Overstating business use is a major HMRC trigger.

What You Cannot Claim (Very Common Errors)

HMRC frequently disallows:

• Home-to-work commuting
• School runs or personal errands
• Dual-purpose journeys without apportionment
• Entire vehicle costs where private use exists

What Happens If HMRC Reviews Your Car Claims?

During a compliance check, HMRC may ask for mileage logs, ownership details, insurance documents, fuel receipts, and lease agreements. If errors are found, expenses are disallowed, tax is recalculated, and penalties (up to 30% or more) are applied.

Why You Should Seek Professional Advice Before Claiming

Car expense rules differ depending on business structure, ownership, vehicle type, and usage patterns. At Mayfair Tax Advisors, we assess the most tax-efficient structure, review historic claims safely, correct errors before HMRC escalates, and handle HMRC correspondence.

Do Not Assume — Get It Reviewed. If you have put car costs through your company, claimed high mileage, or are unsure how your car is treated for tax, act before HMRC does.

Speak to a specialist before it costs you. Email us at [email protected] or fill out the contact form on our website.