You cannot claim tax relief on disallowed expenses against your taxable income. This is even though you may believe they were paid for as a necessary business expense. This is because incorrect claims can result in penalties from the HMRC, and disallowed expenses cannot be deducted from self-employment income. However, for expenses that aren’t tax deductible, you may leave that line blank on your tax return, whether entering a lump sum in the short-form self-employment section or itemising each expense elsewhere.

Getting from home to office: If you run a business out of rented office space, getting to and from the office is a nondeductible expense. In addition, you can claim business trips to clients and other suppliers.

Entertainment Expenses: It doesn’t matter how directly or indirectly connected it is to the job; entertaining clients is never a legitimate business expense. It is possible to claim gifts to clients under certain circumstances. For example, to win a new contract or solidify a business relationship with them, you can take them out to dinner, but you can’t write off the cost of the meal as a tax-deductible expense.

Penalties: You cannot deduct the cost of any fines or penalties. Some examples include self-assessment penalties, traffic tickets, VAT penalties and late payment surcharges on tax.

Dress clothing: In rare circumstances, a self-employed person can claim clothing expenses off their taxable tax. As a result, if the following conditions are met, the cost of your clothing can be considered a legitimate business expense:

• Clothing that resembles a uniform
• Wear the necessary safety clothing for your job;
• You must dress the part if you are an actress or performer.

The cost of any other apparel is quite unlikely to be a deductible expense. 

Daily Meals: Your regular, everyday expense cannot be claimed from your earnings as a sole trader. However, you may be eligible to submit a claim for meals if you are not at your regular workplace. 

Salary: As a sole trader, you cannot pay yourself a salary or wage. Therefore, your taxable profit is determined by total business sales less tax-deductible operating expenses (excluding any money drawn as salary).