Disallowable Expenses: What Businesses Cannot Claim for Tax

When working out what tax is owed, not every cost that appears in a business’s accounts can be deducted. These are known as Disallowable Expenses, and getting them wrong can lead to an inaccurate tax return. 

It is essential to understand which costs HMRC allows and which it does not as it helps in calculating taxable profit correctly.  It matters because HMRC looks closely at different categories of expense, and a business that misclassifies costs consistently risks queries, corrections, and in some situations penalties down the line.

What Are Disallowable Expenses?

A Disallowable Expense is a cost that appears in the account of a business but can not be deducted when calculating taxable profit.  This is different from an ordinary accounting expense. Something can be legitimate, recorded cost of running the business and still not be eligible for tax relief. 

HMRC requires that a deductible expense be incurred “wholly and exclusively” for the purpose of trade. If a cost fails this test, it becomes disallowable. This means that a business does not simply leave disallowable costs out of its account. 

They are recorded normally, but then added back to accounting profit when calculating the figure that tax is actually charged on. The adjustment from accounting profit to taxable profit is essential to how UK business tax returns operate. 

Common Disallowable Expenses for Businesses

Several categories come up repeatedly across UK businesses of all sizes:

• Client and business entertainment
• Fines and penalties for breaking the law
• Personal expenses and the private element of mixed-use costs
• Certain legal and professional fees, particularly those connected to capital transactions
• Depreciation recorded in the accounts
• Political donations and certain charitable payments

This exact treatment within each of these categories can depend on the circumstances and in some situations, on the type of business structure. A cost that has been disallowed for a Sole Trader is not always treated the same way for a limited company, specifically around legal fees and administrative costs. The sections below go deeper into detail regarding the most significant categories. 

Business Entertainment and Gifts

Client and customer entertainment is one of the most misunderstood sections. HMRC clearly disallows expenditure on business entertainment, described broadly as hospitality of any type, given to anyone who is not an employee of the business. This applies even when entertaining is a genuine part of building a relationship with the client. 

For example, taking a potential customer to lunch, funding the cost of tickets to a sports event, or hosting clients at a corporate event all lie in the disallowable category. 

Staff entertainment is treated differently, where entrainment is exclusively applied to employees. For example, a Christmas party or a team’s social event , the cost incurred here is generally considered allowable. 

But this exception is not applicable if the staff entertaining is incidental to entertaining non-employees. For instance, if an employee’s meal is just a part of a client’s lunch, HMRC considers the whole cost as business entertainment. 

Business gifts are also treated in a similar manner and are disallowed as entertainment. But there is an exception: gifts carrying advertisements for the business, £50 or less per recipient in the relevant tax period, are allowable. Provided the gift is not drink, food, tobacco, or a voucher exchangeable for goods. This exception is designed for branded items like diaries, pens, or mouse mats. Gifts to employees are treated separately and are generally considered allowable.

Personal and Mixed-Use Expenses

Regardless of how the payment was made or which account it came from, Personal expenditure can not be claimed against business profits. Phones, vehicles, and travel are the classic examples, utilised for both business and private use in a way that is hard to separate perfectly.

When a business cost has both business and private elements, according to HMRC rules, the identifiable business proportion can be claimed if that proportion can be established and supported. 

This is why evidence is important. A business phone bill that was 60% used for business and 40% for personal use, there needs to be supporting evidence behind the split, call records,  or a mileage log, instead of a number selected because it feels about right. Without proper records, it is harder to defend a claim. 

Capital Expenditure and Depreciation

Costs that come from the everyday running of a business are treated differently from money spent on long-term assets such as machinery, vans or office equipment. 

Revenue expenditure covers the ordinary costs of running the business, while capital expenditure is money spent on assets that provide a lasting benefit to the business. Knowing the difference is an important part of understanding how UK tax rules apply to your business. 

The accounting method for spreading an asset’s cost over its useful life, known as Depreciation, is a standard part of preparing a set of accounts, but it is not a figure HMRC accepts for tax purposes. Depreciation is disallowed and added back when calculating taxable profit.

In its place, Tax Relief on qualifying capital expenditure is generally given through capital allowances, a separate system with its own rules on rates, timing, and which assets qualify. Not all capital expenditure is treated the same way under this system. The specific rate and method depend on the type of asset, when it was bought, and the rules at the time, so it is not safe to assume one type of capital purchase will be treated identically to another.

Fines, Penalties and Other Non-Deductible Costs

Fines and penalties arising from a breach of the law are not considered allowable. HMRC states that where a penalty is intended as a punishment, it fails the wholly and exclusively test and can not be deducted, regardless of how directly it came from a trading activity. 

A parking fine attained on a business trip, a penalty, or a fine after prosecution of breaching regulations are all a part of this category. 

It is worth differentiating penalties from certain compensatory or contractual payments, which are not always treated the same way. A payment made in settlement of a civil action can be allowable, specifically where liability was neither admitted nor proved, or where the payment was restitutionary in nature.           

If a business pays money to settle a civil case, the payment may be deductible if it is mainly compensating someone for a genuine loss. But if it is effectively a punishment or penalty for wrongdoing, it will usually not be deductible. 

Some costs are not as straightforward and need to be looked at individually. 

For instance, legal and professional fees for purchasing or restructuring a capital asset are generally considered Capital costs rather than normal day-to-day expenses. The best option is to look at what the cost was for and why it was incurred, instead of only depending on how it is recorded in the accounts. 

How Disallowable Expenses Affect Your Tax Bill

It is important to understand disallowable expenses because of how they feed into your tax calculation. A business begins with its accounting profit, as depicted in its profit and loss account. It then adds back any disallowable expenses to arrive at its taxable profit, which is the figure used to calculate the tax due. 

Let’s take the following example: say a business has an accounting profit of £50,000 a year and within that figure, £3,000 was for client entertainment and £1,000 to depreciation on office equipment. Both of these are considered disallowable, so £4,000 is added back as:

£50,000 (accounting profit) + £4,000 (disallowable expenses added back) = £54,000 (taxable profit)

Tax is calculated on £54,000. This is why a business should not assume a cost automatically reduces its tax bill simply because it seems that way legitimately, in the profit and loss account.

Keeping Your Expense Claims Tax-Compliant

A few simple habits can help you keep your expenses organised and make sure they are recorded correctly throughout the year, rather than having to work everything out at the end. 

• Keep invoices, receipts and supporting documentation organised.
• Categorise expenses consistently throughout the year. 
• Separate personal and business transactions wherever possible. 
• Review unusual or significant expenses before submitting a tax return. 
• Seek advice where the tax treatment of an expense is unclear. 

This does not need to be complicated, but it requires consistency. Most disallowable expense errors come from inconsistent categorisation over the course of a year, not from a single wrong decision. 

Conclusion

Understanding disallowable expenses helps your business calculate its taxable profit correctly and avoid adjustments at the end of the year. However, whether an expense is considered allowable is dependent on the type of cost and the circumstances in which it was incurred. Two expenses that look the same may receive different tax treatment.

If you are unsure whether your business expenses are allowable for tax purposes, Heighten Accountants can help you review your expenses, identify potential tax deductions, and keep your business compliant with HMRC requirements.